[javascript] HTTP GET request in JavaScript?

I need to do an HTTP GET request in JavaScript. What's the best way to do that?

I need to do this in a Mac OS X dashcode widget.

A copy-paste modern version ( using fetch and arrow function ) :

//Option with catch
fetch( textURL )
   .then(async r=> console.log(await r.text()))
   .catch(e=>console.error('Boo...' + e));

//No fear...
(async () =>
    console.log(
            (await (await fetch( jsonURL )).json())
            )
)();

A copy-paste classic version:

let request = new XMLHttpRequest();
request.onreadystatechange = function () {
    if (this.readyState === 4) {
        if (this.status === 200) {
            document.body.className = 'ok';
            console.log(this.responseText);
        } else if (this.response == null && this.status === 0) {
            document.body.className = 'error offline';
            console.log("The computer appears to be offline.");
        } else {
            document.body.className = 'error';
        }
    }
};
request.open("GET", url, true);
request.send(null);

function get(path) {
    var form = document.createElement("form");
    form.setAttribute("method", "get");
    form.setAttribute("action", path);
    document.body.appendChild(form);
    form.submit();
}


get('/my/url/')

Same thing can be done for post request as well.
Have a look at this link JavaScript post request like a form submit

IE will cache URLs in order to make loading faster, but if you're, say, polling a server at intervals trying to get new information, IE will cache that URL and will likely return the same data set you've always had.

Regardless of how you end up doing your GET request - vanilla JavaScript, Prototype, jQuery, etc - make sure that you put a mechanism in place to combat caching. In order to combat that, append a unique token to the end of the URL you're going to be hitting. This can be done by:

var sURL = '/your/url.html?' + (new Date()).getTime();

This will append a unique timestamp to the end of the URL and will prevent any caching from happening.

Modern, clean and shortest

fetch('https://www.randomtext.me/api/lorem')

let url = 'https://www.randomtext.me/api/lorem';

// to only send GET request without waiting for response just call 
fetch(url);

// to wait for results use 'then'
fetch(url).then(r=> r.json().then(j=> console.log('\nREQUEST 2',j)));

// or async/await
(async()=> 
  console.log('\nREQUEST 3', await(await fetch(url)).json()) 
)();

Open Chrome console network tab to see request

You can get an HTTP GET request in two ways:

1. This approach based on xml format. You have to pass the URL for the request.

   xmlhttp.open("GET","URL",true);
   xmlhttp.send();
   

2. This one is based on jQuery. You have to specify the URL and function_name you want to call.

   $("btn").click(function() {
     $.ajax({url: "demo_test.txt", success: function_name(result) {
       $("#innerdiv").html(result);
     }});
   }); 
   

To refresh best answer from joann with promise this is my code:

let httpRequestAsync = (method, url) => {
    return new Promise(function (resolve, reject) {
        var xhr = new XMLHttpRequest();
        xhr.open(method, url);
        xhr.onload = function () {
            if (xhr.status == 200) {
                resolve(xhr.responseText);
            }
            else {
                reject(new Error(xhr.responseText));
            }
        };
        xhr.send();
    });
}

Ajax

You'd be best off using a library such as Prototype or jQuery.

The best way is to use AJAX ( you can find a simple tutorial on this page Tizag). The reason is that any other technique you may use requires more code, it is not guaranteed to work cross browser without rework and requires you use more client memory by opening hidden pages inside frames passing urls parsing their data and closing them. AJAX is the way to go in this situation. That my two years of javascript heavy development speaking.

In your widget's Info.plist file, don't forget to set your AllowNetworkAccess key to true.

Here is code to do it directly with JavaScript. But, as previously mentioned, you'd be much better off with a JavaScript library. My favorite is jQuery.

In the case below, an ASPX page (that's servicing as a poor man's REST service) is being called to return a JavaScript JSON object.

var xmlHttp = null;

function GetCustomerInfo()
{
    var CustomerNumber = document.getElementById( "TextBoxCustomerNumber" ).value;
    var Url = "GetCustomerInfoAsJson.aspx?number=" + CustomerNumber;

    xmlHttp = new XMLHttpRequest(); 
    xmlHttp.onreadystatechange = ProcessRequest;
    xmlHttp.open( "GET", Url, true );
    xmlHttp.send( null );
}

function ProcessRequest() 
{
    if ( xmlHttp.readyState == 4 && xmlHttp.status == 200 ) 
    {
        if ( xmlHttp.responseText == "Not found" ) 
        {
            document.getElementById( "TextBoxCustomerName"    ).value = "Not found";
            document.getElementById( "TextBoxCustomerAddress" ).value = "";
        }
        else
        {
            var info = eval ( "(" + xmlHttp.responseText + ")" );

            // No parsing necessary with JSON!        
            document.getElementById( "TextBoxCustomerName"    ).value = info.jsonData[ 0 ].cmname;
            document.getElementById( "TextBoxCustomerAddress" ).value = info.jsonData[ 0 ].cmaddr1;
        }                    
    }
}

IE will cache URLs in order to make loading faster, but if you're, say, polling a server at intervals trying to get new information, IE will cache that URL and will likely return the same data set you've always had.

Regardless of how you end up doing your GET request - vanilla JavaScript, Prototype, jQuery, etc - make sure that you put a mechanism in place to combat caching. In order to combat that, append a unique token to the end of the URL you're going to be hitting. This can be done by:

var sURL = '/your/url.html?' + (new Date()).getTime();

This will append a unique timestamp to the end of the URL and will prevent any caching from happening.

For those who use AngularJs, it's $http.get:

$http.get('/someUrl').
  success(function(data, status, headers, config) {
    // this callback will be called asynchronously
    // when the response is available
  }).
  error(function(data, status, headers, config) {
    // called asynchronously if an error occurs
    // or server returns response with an error status.
  });

I'm not familiar with Mac OS Dashcode Widgets, but if they let you use JavaScript libraries and support XMLHttpRequests, I'd use jQuery and do something like this:

var page_content;
$.get( "somepage.php", function(data){
    page_content = data;
});

In your widget's Info.plist file, don't forget to set your AllowNetworkAccess key to true.

Simple async request:

function get(url, callback) {
  var getRequest = new XMLHttpRequest();

  getRequest.open("get", url, true);

  getRequest.addEventListener("readystatechange", function() {
    if (getRequest.readyState === 4 && getRequest.status === 200) {
      callback(getRequest.responseText);
    }
  });

  getRequest.send();
}

I'm not familiar with Mac OS Dashcode Widgets, but if they let you use JavaScript libraries and support XMLHttpRequests, I'd use jQuery and do something like this:

var page_content;
$.get( "somepage.php", function(data){
    page_content = data;
});

Here is code to do it directly with JavaScript. But, as previously mentioned, you'd be much better off with a JavaScript library. My favorite is jQuery.

In the case below, an ASPX page (that's servicing as a poor man's REST service) is being called to return a JavaScript JSON object.

var xmlHttp = null;

function GetCustomerInfo()
{
    var CustomerNumber = document.getElementById( "TextBoxCustomerNumber" ).value;
    var Url = "GetCustomerInfoAsJson.aspx?number=" + CustomerNumber;

    xmlHttp = new XMLHttpRequest(); 
    xmlHttp.onreadystatechange = ProcessRequest;
    xmlHttp.open( "GET", Url, true );
    xmlHttp.send( null );
}

function ProcessRequest() 
{
    if ( xmlHttp.readyState == 4 && xmlHttp.status == 200 ) 
    {
        if ( xmlHttp.responseText == "Not found" ) 
        {
            document.getElementById( "TextBoxCustomerName"    ).value = "Not found";
            document.getElementById( "TextBoxCustomerAddress" ).value = "";
        }
        else
        {
            var info = eval ( "(" + xmlHttp.responseText + ")" );

            // No parsing necessary with JSON!        
            document.getElementById( "TextBoxCustomerName"    ).value = info.jsonData[ 0 ].cmname;
            document.getElementById( "TextBoxCustomerAddress" ).value = info.jsonData[ 0 ].cmaddr1;
        }                    
    }
}

<button type="button" onclick="loadXMLDoc()"> GET CONTENT</button>

 <script>
        function loadXMLDoc() {
            var xmlhttp = new XMLHttpRequest();
            var url = "<Enter URL>";``
            xmlhttp.onload = function () {
                if (xmlhttp.readyState == 4 && xmlhttp.status == "200") {
                    document.getElementById("demo").innerHTML = this.responseText;
                }
            }
            xmlhttp.open("GET", url, true);
            xmlhttp.send();
        }
    </script>

Ajax

You'd be best off using a library such as Prototype or jQuery.

To refresh best answer from joann with promise this is my code:

let httpRequestAsync = (method, url) => {
    return new Promise(function (resolve, reject) {
        var xhr = new XMLHttpRequest();
        xhr.open(method, url);
        xhr.onload = function () {
            if (xhr.status == 200) {
                resolve(xhr.responseText);
            }
            else {
                reject(new Error(xhr.responseText));
            }
        };
        xhr.send();
    });
}

Short and clean:

const http = new XMLHttpRequest()_x000D_
_x000D_
http.open("GET", "https://api.lyrics.ovh/v1/toto/africa")_x000D_
http.send()_x000D_
_x000D_
http.onload = () => console.log(http.responseText)

I'm not familiar with Mac OS Dashcode Widgets, but if they let you use JavaScript libraries and support XMLHttpRequests, I'd use jQuery and do something like this:

var page_content;
$.get( "somepage.php", function(data){
    page_content = data;
});

If you want to use the code for a Dashboard widget, and you don't want to include a JavaScript library in every widget you created, then you can use the object XMLHttpRequest that Safari natively supports.

As reported by Andrew Hedges, a widget doesn't have access to a network, by default; you need to change that setting in the info.plist associated with the widget.

<button type="button" onclick="loadXMLDoc()"> GET CONTENT</button>

 <script>
        function loadXMLDoc() {
            var xmlhttp = new XMLHttpRequest();
            var url = "<Enter URL>";``
            xmlhttp.onload = function () {
                if (xmlhttp.readyState == 4 && xmlhttp.status == "200") {
                    document.getElementById("demo").innerHTML = this.responseText;
                }
            }
            xmlhttp.open("GET", url, true);
            xmlhttp.send();
        }
    </script>

Lots of great advice above, but not very reusable, and too often filled with DOM nonsense and other fluff that hides the easy code.

Here's a Javascript class we created that's reusable and easy to use. Currently it only has a GET method, but that works for us. Adding a POST shouldn't tax anyone's skills.

var HttpClient = function() {
    this.get = function(aUrl, aCallback) {
        var anHttpRequest = new XMLHttpRequest();
        anHttpRequest.onreadystatechange = function() { 
            if (anHttpRequest.readyState == 4 && anHttpRequest.status == 200)
                aCallback(anHttpRequest.responseText);
        }

        anHttpRequest.open( "GET", aUrl, true );            
        anHttpRequest.send( null );
    }
}

Using it is as easy as:

var client = new HttpClient();
client.get('http://some/thing?with=arguments', function(response) {
    // do something with response
});

In jQuery:

$.get(
    "somepage.php",
    {paramOne : 1, paramX : 'abc'},
    function(data) {
       alert('page content: ' + data);
    }
);

You can get an HTTP GET request in two ways:

1. This approach based on xml format. You have to pass the URL for the request.

   xmlhttp.open("GET","URL",true);
   xmlhttp.send();
   

2. This one is based on jQuery. You have to specify the URL and function_name you want to call.

   $("btn").click(function() {
     $.ajax({url: "demo_test.txt", success: function_name(result) {
       $("#innerdiv").html(result);
     }});
   }); 
   

The best way is to use AJAX ( you can find a simple tutorial on this page Tizag). The reason is that any other technique you may use requires more code, it is not guaranteed to work cross browser without rework and requires you use more client memory by opening hidden pages inside frames passing urls parsing their data and closing them. AJAX is the way to go in this situation. That my two years of javascript heavy development speaking.

If you want to use the code for a Dashboard widget, and you don't want to include a JavaScript library in every widget you created, then you can use the object XMLHttpRequest that Safari natively supports.

As reported by Andrew Hedges, a widget doesn't have access to a network, by default; you need to change that setting in the info.plist associated with the widget.

Lots of great advice above, but not very reusable, and too often filled with DOM nonsense and other fluff that hides the easy code.

Here's a Javascript class we created that's reusable and easy to use. Currently it only has a GET method, but that works for us. Adding a POST shouldn't tax anyone's skills.

var HttpClient = function() {
    this.get = function(aUrl, aCallback) {
        var anHttpRequest = new XMLHttpRequest();
        anHttpRequest.onreadystatechange = function() { 
            if (anHttpRequest.readyState == 4 && anHttpRequest.status == 200)
                aCallback(anHttpRequest.responseText);
        }

        anHttpRequest.open( "GET", aUrl, true );            
        anHttpRequest.send( null );
    }
}

Using it is as easy as:

var client = new HttpClient();
client.get('http://some/thing?with=arguments', function(response) {
    // do something with response
});

I'm not familiar with Mac OS Dashcode Widgets, but if they let you use JavaScript libraries and support XMLHttpRequests, I'd use jQuery and do something like this:

var page_content;
$.get( "somepage.php", function(data){
    page_content = data;
});

Simple async request:

function get(url, callback) {
  var getRequest = new XMLHttpRequest();

  getRequest.open("get", url, true);

  getRequest.addEventListener("readystatechange", function() {
    if (getRequest.readyState === 4 && getRequest.status === 200) {
      callback(getRequest.responseText);
    }
  });

  getRequest.send();
}

You can do it with pure JS too:

// Create the XHR object.
function createCORSRequest(method, url) {
  var xhr = new XMLHttpRequest();
if ("withCredentials" in xhr) {
// XHR for Chrome/Firefox/Opera/Safari.
xhr.open(method, url, true);
} else if (typeof XDomainRequest != "undefined") {
// XDomainRequest for IE.
xhr = new XDomainRequest();
xhr.open(method, url);
} else {
// CORS not supported.
xhr = null;
}
return xhr;
}

// Make the actual CORS request.
function makeCorsRequest() {
 // This is a sample server that supports CORS.
 var url = 'http://html5rocks-cors.s3-website-us-east-1.amazonaws.com/index.html';

var xhr = createCORSRequest('GET', url);
if (!xhr) {
alert('CORS not supported');
return;
}

// Response handlers.
xhr.onload = function() {
var text = xhr.responseText;
alert('Response from CORS request to ' + url + ': ' + text);
};

xhr.onerror = function() {
alert('Woops, there was an error making the request.');
};

xhr.send();
}

See: for more details: html5rocks tutorial

To do this Fetch API is the recommended approach, using JavaScript Promises. XMLHttpRequest (XHR), IFrame object or dynamic tags are older (and clunkier) approaches.

<script type=“text/javascript”> 
    // Create request object 
    var request = new Request('https://example.com/api/...', 
         { method: 'POST', 
           body: {'name': 'Klaus'}, 
           headers: new Headers({ 'Content-Type': 'application/json' }) 
         });
    // Now use it! 

   fetch(request) 
   .then(resp => { 
         // handle response }) 
   .catch(err => { 
         // handle errors 
    }); </script>

Here is a great fetch demo and MDN docs

Ajax

You'd be best off using a library such as Prototype or jQuery.

One solution supporting older browsers:

function httpRequest() {
    var ajax = null,
        response = null,
        self = this;

    this.method = null;
    this.url = null;
    this.async = true;
    this.data = null;

    this.send = function() {
        ajax.open(this.method, this.url, this.asnyc);
        ajax.send(this.data);
    };

    if(window.XMLHttpRequest) {
        ajax = new XMLHttpRequest();
    }
    else if(window.ActiveXObject) {
        try {
            ajax = new ActiveXObject("Msxml2.XMLHTTP.6.0");
        }
        catch(e) {
            try {
                ajax = new ActiveXObject("Msxml2.XMLHTTP.3.0");
            }
            catch(error) {
                self.fail("not supported");
            }
        }
    }

    if(ajax == null) {
        return false;
    }

    ajax.onreadystatechange = function() {
        if(this.readyState == 4) {
            if(this.status == 200) {
                self.success(this.responseText);
            }
            else {
                self.fail(this.status + " - " + this.statusText);
            }
        }
    };
}

Maybe somewhat overkill but you definitely go safe with this code.

Usage:

//create request with its porperties
var request = new httpRequest();
request.method = "GET";
request.url = "https://example.com/api?parameter=value";

//create callback for success containing the response
request.success = function(response) {
    console.log(response);
};

//and a fail callback containing the error
request.fail = function(error) {
    console.log(error);
};

//and finally send it away
request.send();

Prototype makes it dead simple

new Ajax.Request( '/myurl', {
  method:  'get',
  parameters:  { 'param1': 'value1'},
  onSuccess:  function(response){
    alert(response.responseText);
  },
  onFailure:  function(){
    alert('ERROR');
  }
});

In jQuery:

$.get(
    "somepage.php",
    {paramOne : 1, paramX : 'abc'},
    function(data) {
       alert('page content: ' + data);
    }
);

In your widget's Info.plist file, don't forget to set your AllowNetworkAccess key to true.

Here is an alternative to xml files to load your files as an object and access properties as an object in a very fast way.

• Attention, so that javascript can him and to interpret the content correctly it is necessary to save your files in the same format as your HTML page. If you use UTF 8 save your files in UTF8, etc.

XML works as a tree ok? instead of writing

     <property> value <property> 

write a simple file like this:

      Property1: value
      Property2: value
      etc.

Save your file .. Now call the function ....

    var objectfile = {};

function getfilecontent(url){
    var cli = new XMLHttpRequest();

    cli.onload = function(){
         if((this.status == 200 || this.status == 0) && this.responseText != null) {
        var r = this.responseText;
        var b=(r.indexOf('\n')?'\n':r.indexOf('\r')?'\r':'');
        if(b.length){
        if(b=='\n'){var j=r.toString().replace(/\r/gi,'');}else{var j=r.toString().replace(/\n/gi,'');}
        r=j.split(b);
        r=r.filter(function(val){if( val == '' || val == NaN || val == undefined || val == null ){return false;}return true;});
        r = r.map(f => f.trim());
        }
        if(r.length > 0){
            for(var i=0; i<r.length; i++){
                var m = r[i].split(':');
                if(m.length>1){
                        var mname = m[0];
                        var n = m.shift();
                        var ivalue = m.join(':');
                        objectfile[mname]=ivalue;
                }
            }
        }
        }
    }
cli.open("GET", url);
cli.send();
}

now you can get your values efficiently.

getfilecontent('mesite.com/mefile.txt');

window.onload = function(){

if(objectfile !== null){
alert (objectfile.property1.value);
}
}

It's just a small gift to contibute to the group. Thanks of your like :)

If you want to test the function on your PC locally, restart your browser with the following command (supported by all browsers except safari):

yournavigator.exe '' --allow-file-access-from-files

IE will cache URLs in order to make loading faster, but if you're, say, polling a server at intervals trying to get new information, IE will cache that URL and will likely return the same data set you've always had.

Regardless of how you end up doing your GET request - vanilla JavaScript, Prototype, jQuery, etc - make sure that you put a mechanism in place to combat caching. In order to combat that, append a unique token to the end of the URL you're going to be hitting. This can be done by:

var sURL = '/your/url.html?' + (new Date()).getTime();

This will append a unique timestamp to the end of the URL and will prevent any caching from happening.

A version without callback

var i = document.createElement("img");
i.src = "/your/GET/url?params=here";

Prototype makes it dead simple

new Ajax.Request( '/myurl', {
  method:  'get',
  parameters:  { 'param1': 'value1'},
  onSuccess:  function(response){
    alert(response.responseText);
  },
  onFailure:  function(){
    alert('ERROR');
  }
});

In your widget's Info.plist file, don't forget to set your AllowNetworkAccess key to true.

The best way is to use AJAX ( you can find a simple tutorial on this page Tizag). The reason is that any other technique you may use requires more code, it is not guaranteed to work cross browser without rework and requires you use more client memory by opening hidden pages inside frames passing urls parsing their data and closing them. AJAX is the way to go in this situation. That my two years of javascript heavy development speaking.

Here is an alternative to xml files to load your files as an object and access properties as an object in a very fast way.

• Attention, so that javascript can him and to interpret the content correctly it is necessary to save your files in the same format as your HTML page. If you use UTF 8 save your files in UTF8, etc.

XML works as a tree ok? instead of writing

     <property> value <property> 

write a simple file like this:

      Property1: value
      Property2: value
      etc.

Save your file .. Now call the function ....

    var objectfile = {};

function getfilecontent(url){
    var cli = new XMLHttpRequest();

    cli.onload = function(){
         if((this.status == 200 || this.status == 0) && this.responseText != null) {
        var r = this.responseText;
        var b=(r.indexOf('\n')?'\n':r.indexOf('\r')?'\r':'');
        if(b.length){
        if(b=='\n'){var j=r.toString().replace(/\r/gi,'');}else{var j=r.toString().replace(/\n/gi,'');}
        r=j.split(b);
        r=r.filter(function(val){if( val == '' || val == NaN || val == undefined || val == null ){return false;}return true;});
        r = r.map(f => f.trim());
        }
        if(r.length > 0){
            for(var i=0; i<r.length; i++){
                var m = r[i].split(':');
                if(m.length>1){
                        var mname = m[0];
                        var n = m.shift();
                        var ivalue = m.join(':');
                        objectfile[mname]=ivalue;
                }
            }
        }
        }
    }
cli.open("GET", url);
cli.send();
}

now you can get your values efficiently.

getfilecontent('mesite.com/mefile.txt');

window.onload = function(){

if(objectfile !== null){
alert (objectfile.property1.value);
}
}

It's just a small gift to contibute to the group. Thanks of your like :)

If you want to test the function on your PC locally, restart your browser with the following command (supported by all browsers except safari):

yournavigator.exe '' --allow-file-access-from-files

function get(path) {
    var form = document.createElement("form");
    form.setAttribute("method", "get");
    form.setAttribute("action", path);
    document.body.appendChild(form);
    form.submit();
}


get('/my/url/')

Same thing can be done for post request as well.
Have a look at this link JavaScript post request like a form submit

In jQuery:

$.get(
    "somepage.php",
    {paramOne : 1, paramX : 'abc'},
    function(data) {
       alert('page content: ' + data);
    }
);

A version without callback

var i = document.createElement("img");
i.src = "/your/GET/url?params=here";

One solution supporting older browsers:

function httpRequest() {
    var ajax = null,
        response = null,
        self = this;

    this.method = null;
    this.url = null;
    this.async = true;
    this.data = null;

    this.send = function() {
        ajax.open(this.method, this.url, this.asnyc);
        ajax.send(this.data);
    };

    if(window.XMLHttpRequest) {
        ajax = new XMLHttpRequest();
    }
    else if(window.ActiveXObject) {
        try {
            ajax = new ActiveXObject("Msxml2.XMLHTTP.6.0");
        }
        catch(e) {
            try {
                ajax = new ActiveXObject("Msxml2.XMLHTTP.3.0");
            }
            catch(error) {
                self.fail("not supported");
            }
        }
    }

    if(ajax == null) {
        return false;
    }

    ajax.onreadystatechange = function() {
        if(this.readyState == 4) {
            if(this.status == 200) {
                self.success(this.responseText);
            }
            else {
                self.fail(this.status + " - " + this.statusText);
            }
        }
    };
}

Maybe somewhat overkill but you definitely go safe with this code.

Usage:

//create request with its porperties
var request = new httpRequest();
request.method = "GET";
request.url = "https://example.com/api?parameter=value";

//create callback for success containing the response
request.success = function(response) {
    console.log(response);
};

//and a fail callback containing the error
request.fail = function(error) {
    console.log(error);
};

//and finally send it away
request.send();

Ajax

You'd be best off using a library such as Prototype or jQuery.

You can do it with pure JS too:

// Create the XHR object.
function createCORSRequest(method, url) {
  var xhr = new XMLHttpRequest();
if ("withCredentials" in xhr) {
// XHR for Chrome/Firefox/Opera/Safari.
xhr.open(method, url, true);
} else if (typeof XDomainRequest != "undefined") {
// XDomainRequest for IE.
xhr = new XDomainRequest();
xhr.open(method, url);
} else {
// CORS not supported.
xhr = null;
}
return xhr;
}

// Make the actual CORS request.
function makeCorsRequest() {
 // This is a sample server that supports CORS.
 var url = 'http://html5rocks-cors.s3-website-us-east-1.amazonaws.com/index.html';

var xhr = createCORSRequest('GET', url);
if (!xhr) {
alert('CORS not supported');
return;
}

// Response handlers.
xhr.onload = function() {
var text = xhr.responseText;
alert('Response from CORS request to ' + url + ': ' + text);
};

xhr.onerror = function() {
alert('Woops, there was an error making the request.');
};

xhr.send();
}

See: for more details: html5rocks tutorial

To do this Fetch API is the recommended approach, using JavaScript Promises. XMLHttpRequest (XHR), IFrame object or dynamic tags are older (and clunkier) approaches.

<script type=“text/javascript”> 
    // Create request object 
    var request = new Request('https://example.com/api/...', 
         { method: 'POST', 
           body: {'name': 'Klaus'}, 
           headers: new Headers({ 'Content-Type': 'application/json' }) 
         });
    // Now use it! 

   fetch(request) 
   .then(resp => { 
         // handle response }) 
   .catch(err => { 
         // handle errors 
    }); </script>

Here is a great fetch demo and MDN docs

For those who use AngularJs, it's $http.get:

$http.get('/someUrl').
  success(function(data, status, headers, config) {
    // this callback will be called asynchronously
    // when the response is available
  }).
  error(function(data, status, headers, config) {
    // called asynchronously if an error occurs
    // or server returns response with an error status.
  });

Short and clean:

const http = new XMLHttpRequest()_x000D_
_x000D_
http.open("GET", "https://api.lyrics.ovh/v1/toto/africa")_x000D_
http.send()_x000D_
_x000D_
http.onload = () => console.log(http.responseText)

Here is code to do it directly with JavaScript. But, as previously mentioned, you'd be much better off with a JavaScript library. My favorite is jQuery.

In the case below, an ASPX page (that's servicing as a poor man's REST service) is being called to return a JavaScript JSON object.

var xmlHttp = null;

function GetCustomerInfo()
{
    var CustomerNumber = document.getElementById( "TextBoxCustomerNumber" ).value;
    var Url = "GetCustomerInfoAsJson.aspx?number=" + CustomerNumber;

    xmlHttp = new XMLHttpRequest(); 
    xmlHttp.onreadystatechange = ProcessRequest;
    xmlHttp.open( "GET", Url, true );
    xmlHttp.send( null );
}

function ProcessRequest() 
{
    if ( xmlHttp.readyState == 4 && xmlHttp.status == 200 ) 
    {
        if ( xmlHttp.responseText == "Not found" ) 
        {
            document.getElementById( "TextBoxCustomerName"    ).value = "Not found";
            document.getElementById( "TextBoxCustomerAddress" ).value = "";
        }
        else
        {
            var info = eval ( "(" + xmlHttp.responseText + ")" );

            // No parsing necessary with JSON!        
            document.getElementById( "TextBoxCustomerName"    ).value = info.jsonData[ 0 ].cmname;
            document.getElementById( "TextBoxCustomerAddress" ).value = info.jsonData[ 0 ].cmaddr1;
        }                    
    }
}

The new window.fetch API is a cleaner replacement for XMLHttpRequest that makes use of ES6 promises. There's a nice explanation here, but it boils down to (from the article):

fetch(url).then(function(response) {
  return response.json();
}).then(function(data) {
  console.log(data);
}).catch(function() {
  console.log("Booo");
});

Browser support is now good in the latest releases (works in Chrome, Firefox, Edge (v14), Safari (v10.1), Opera, Safari iOS (v10.3), Android browser, and Chrome for Android), however IE will likely not get official support. GitHub has a polyfill available which is recommended to support older browsers still largely in use (esp versions of Safari pre March 2017 and mobile browsers from the same period).

I guess whether this is more convenient than jQuery or XMLHttpRequest or not depends on the nature of the project.

Here's a link to the spec https://fetch.spec.whatwg.org/

Edit:

Using ES7 async/await, this becomes simply (based on this Gist):

async function fetchAsync (url) {
  let response = await fetch(url);
  let data = await response.json();
  return data;
}

Prototype makes it dead simple

new Ajax.Request( '/myurl', {
  method:  'get',
  parameters:  { 'param1': 'value1'},
  onSuccess:  function(response){
    alert(response.responseText);
  },
  onFailure:  function(){
    alert('ERROR');
  }
});

// Create a request variable and assign a new XMLHttpRequest object to it.
var request = new XMLHttpRequest()

// Open a new connection, using the GET request on the URL endpoint
request.open('GET', 'restUrl', true)

request.onload = function () {
  // Begin accessing JSON data here
}

// Send request
request.send()

Modern, clean and shortest

fetch('https://www.randomtext.me/api/lorem')

let url = 'https://www.randomtext.me/api/lorem';

// to only send GET request without waiting for response just call 
fetch(url);

// to wait for results use 'then'
fetch(url).then(r=> r.json().then(j=> console.log('\nREQUEST 2',j)));

// or async/await
(async()=> 
  console.log('\nREQUEST 3', await(await fetch(url)).json()) 
)();

Open Chrome console network tab to see request

A copy-paste modern version ( using fetch and arrow function ) :

//Option with catch
fetch( textURL )
   .then(async r=> console.log(await r.text()))
   .catch(e=>console.error('Boo...' + e));

//No fear...
(async () =>
    console.log(
            (await (await fetch( jsonURL )).json())
            )
)();

A copy-paste classic version:

let request = new XMLHttpRequest();
request.onreadystatechange = function () {
    if (this.readyState === 4) {
        if (this.status === 200) {
            document.body.className = 'ok';
            console.log(this.responseText);
        } else if (this.response == null && this.status === 0) {
            document.body.className = 'error offline';
            console.log("The computer appears to be offline.");
        } else {
            document.body.className = 'error';
        }
    }
};
request.open("GET", url, true);
request.send(null);

Prototype makes it dead simple

new Ajax.Request( '/myurl', {
  method:  'get',
  parameters:  { 'param1': 'value1'},
  onSuccess:  function(response){
    alert(response.responseText);
  },
  onFailure:  function(){
    alert('ERROR');
  }
});

The best way is to use AJAX ( you can find a simple tutorial on this page Tizag). The reason is that any other technique you may use requires more code, it is not guaranteed to work cross browser without rework and requires you use more client memory by opening hidden pages inside frames passing urls parsing their data and closing them. AJAX is the way to go in this situation. That my two years of javascript heavy development speaking.

Here is code to do it directly with JavaScript. But, as previously mentioned, you'd be much better off with a JavaScript library. My favorite is jQuery.

In the case below, an ASPX page (that's servicing as a poor man's REST service) is being called to return a JavaScript JSON object.

var xmlHttp = null;

function GetCustomerInfo()
{
    var CustomerNumber = document.getElementById( "TextBoxCustomerNumber" ).value;
    var Url = "GetCustomerInfoAsJson.aspx?number=" + CustomerNumber;

    xmlHttp = new XMLHttpRequest(); 
    xmlHttp.onreadystatechange = ProcessRequest;
    xmlHttp.open( "GET", Url, true );
    xmlHttp.send( null );
}

function ProcessRequest() 
{
    if ( xmlHttp.readyState == 4 && xmlHttp.status == 200 ) 
    {
        if ( xmlHttp.responseText == "Not found" ) 
        {
            document.getElementById( "TextBoxCustomerName"    ).value = "Not found";
            document.getElementById( "TextBoxCustomerAddress" ).value = "";
        }
        else
        {
            var info = eval ( "(" + xmlHttp.responseText + ")" );

            // No parsing necessary with JSON!        
            document.getElementById( "TextBoxCustomerName"    ).value = info.jsonData[ 0 ].cmname;
            document.getElementById( "TextBoxCustomerAddress" ).value = info.jsonData[ 0 ].cmaddr1;
        }                    
    }
}

The new window.fetch API is a cleaner replacement for XMLHttpRequest that makes use of ES6 promises. There's a nice explanation here, but it boils down to (from the article):

fetch(url).then(function(response) {
  return response.json();
}).then(function(data) {
  console.log(data);
}).catch(function() {
  console.log("Booo");
});

Browser support is now good in the latest releases (works in Chrome, Firefox, Edge (v14), Safari (v10.1), Opera, Safari iOS (v10.3), Android browser, and Chrome for Android), however IE will likely not get official support. GitHub has a polyfill available which is recommended to support older browsers still largely in use (esp versions of Safari pre March 2017 and mobile browsers from the same period).

I guess whether this is more convenient than jQuery or XMLHttpRequest or not depends on the nature of the project.

Here's a link to the spec https://fetch.spec.whatwg.org/

Edit:

Using ES7 async/await, this becomes simply (based on this Gist):

async function fetchAsync (url) {
  let response = await fetch(url);
  let data = await response.json();
  return data;
}

// Create a request variable and assign a new XMLHttpRequest object to it.
var request = new XMLHttpRequest()

// Open a new connection, using the GET request on the URL endpoint
request.open('GET', 'restUrl', true)

request.onload = function () {
  // Begin accessing JSON data here
}

// Send request
request.send()

In jQuery:

$.get(
    "somepage.php",
    {paramOne : 1, paramX : 'abc'},
    function(data) {
       alert('page content: ' + data);
    }
);