[javascript] jQuery pass more parameters into callback

Is there a way to pass more data into a callback function in jQuery?

I have two functions and I want the callback to the $.post, for example, to pass in both the resulting data of the AJAX call, as well as a few custom arguments

function clicked() {
    var myDiv = $("#my-div");
    // ERROR: Says data not defined
    $.post("someurl.php",someData,doSomething(data, myDiv),"json"); 
    // ERROR: Would pass in myDiv as curData (wrong)
    $.post("someurl.php",someData,doSomething(data, myDiv),"json"); 
}

function doSomething(curData, curDiv) {

}

I want to be able to pass in my own parameters to a callback, as well as the result returned from the AJAX call.

It's actually easier than everyone's making it sound... especially if you use the $.ajax({}) base syntax vs. one of the helper functions.

Just pass in the key: value pair like you would on any object, when you setup your ajax request... (because $(this) hasn't changed context yet, it's still the trigger for the bind call above)

<script type="text/javascript">
$(".qty input").bind("keypress change", function() {
    $.ajax({
        url: "/order_items/change/"+$(this).attr("data-order-item-id")+"/qty:"+$(this).val()+"/returnas.json",
        type: "POST",
        dataType: "json",
        qty_input: $(this),
        anything_else_i_want_to_pass_in: "foo",
        success: function(json_data, textStatus, jqXHR) {
            /* here is the input, which triggered this AJAX request */
            console.log(this.qty_input);
            /* here is any other parameter you set when initializing the ajax method */
            console.log(this.anything_else_i_want_to_pass_in);
        }
    });
});
</script>

One of the reasons this is better than setting the var, is that the var is global and as such, overwritable... if you have 2 things which can trigger ajax calls, you could in theory trigger them faster than ajax call responds, and you'd have the value for the second call passed into the first. Using this method, above, that wouldn't happen (and it's pretty simple to use too).

When using doSomething(data, myDiv), you actually call the function and do not make a reference to it.

You can either pass the doStomething function directly but you must ensure it has the correct signature.

If you want to keep doSomething the way it is, you can wrap its call in an anonymous function.

function clicked() {
    var myDiv = $("#my-div");
    $.post("someurl.php",someData, function(data){ 
      doSomething(data, myDiv)
    },"json"); 
}

function doSomething(curData, curDiv) {
    ...
}

Inside the anonymous function code, you can use the variables defined in the enclosing scope. This is the way Javascript scoping works.

As an addendum to b01's answer, the second argument of $.proxy is often used to preserve the this reference. Additional arguments passed to $.proxy are partially applied to the function, pre-filling it with data. Note that any arguments $.post passes to the callback will be applied at the end, so doSomething should have those at the end of its argument list:

function clicked() {
    var myDiv = $("#my-div");
    var callback = $.proxy(doSomething, this, myDiv);
    $.post("someurl.php",someData,callback,"json"); 
}

function doSomething(curDiv, curData) {
    //"this" still refers to the same "this" as clicked()
    var serverResponse = curData;
}

This approach also allows multiple arguments to be bound to the callback:

function clicked() {
    var myDiv = $("#my-div");
    var mySpan = $("#my-span");
    var isActive = true;
    var callback = $.proxy(doSomething, this, myDiv, mySpan, isActive);
    $.post("someurl.php",someData,callback,"json"); 
}

function doSomething(curDiv, curSpan, curIsActive, curData) {
    //"this" still refers to the same "this" as clicked()
    var serverResponse = curData;
}

A more general solution for sending asynchronous requests using the .ajax() jQuery API and closures to pass additional parameters to the callback function:

function sendRequest(method, url, content, callback) {
    // additional data for the callback
    var request = {
        method: method,
        url: url
    };

    $.ajax({
        type: method,
        url: url,
        data: content
     }).done(function(data, status, xhr) {
        if (callback) callback(xhr.status, data, request);
     }).fail(function(xhr, status) {
        if (callback) callback(xhr.status, xhr.response, request);
     });
};

$(document).on('click','[action=register]',function(){
    registerSocket(registerJSON(),registerDone,second($(this)));
});

function registerSocket(dataFn,doneFn,second){
                 $.ajax({
                       type:'POST',
                       url: "http://localhost:8080/store/public/register",
                       contentType: "application/json; charset=utf-8",
                       dataType: "json",
                       data:dataFn
                 }).done ([doneFn,second])
                   .fail(function(err){
                            console.log("AJAX failed: " + JSON.stringify(err, null, 2));
                        });
}

function registerDone(data){
    console.log(JSON.stringify(data));
}
function second(element){
    console.log(element);
}

Secondary way :

function socketWithParam(url,dataFn,doneFn,param){
  $.ajax({
    type:'POST',
    url:url,
    contentType: "application/json; charset=utf-8",
    headers: { 'Authorization': 'Bearer '+localStorage.getItem('jwt')},
    data:dataFn
    }).done(function(data){
      doneFn(data,param);
    })
    .fail(function(err,status,xhr){
    console.log("AJAX failed: " + JSON.stringify(err, null, 2));
    });
}

$(document).on('click','[order-btn]',function(){
  socketWithParam(url,fakeDataFn(),orderDetailDone,secondParam);
});

function orderDetailDone(data,param){
  -- to do something --
}

You can use a closure of JavaScript:

function wrapper( var1, var2,....) // put here your variables
{
  return function( data, status)
  {
     //Handle here results of call
  }
};

and when you can do:

$.post("someurl.php",data,wrapper(var1, var2, etc...),"html");

If someone still comes here, this is my take:

$('.selector').click(myCallbackFunction.bind({var1: 'hello', var2: 'world'}));

function myCallbackFunction(event) {
    var passedArg1 = this.var1,
        passedArg2 = this.var2
}

What happens here, after binding to the callback function, it will be available within the function as this.

This idea comes from how React uses the bind functionality.

Let's go simple ! :)

$.ajax({
    url: myUrl,
    context: $this, // $this == Current $element
    success: function(data) {
        $.proxy(publicMethods.update, this)(data); // this == Current $element
    }
});

In today's world there is a another answer that is cleaner, and taken from another Stack Overflow answer:

function clicked()
{
    var myDiv = $( "#my-div" );

    $.post( "someurl.php", {"someData": someData}, $.proxy(doSomething, myDiv), "json" );
}

function doSomething( data )
{
    // this will be equal to myDiv now. Thanks to jQuery.proxy().
    var $myDiv = this;

    // doing stuff.
    ...
}

Here's the original question and answer: jQuery HOW TO?? pass additional parameters to success callback for $.ajax call?

I've made a mistake in the last my post. This is working example for how to pass additional argument in callback function:

function custom_func(p1,p2) {
    $.post(AJAX_FILE_PATH,{op:'dosomething',p1:p1},
        function(data){
            return function(){
                alert(data);
                alert(p2);
            }(data,p2)
        }
    );
    return false;
}

For me, and other newbies who has just contacted with Javascript,
I think that the Closeure Solution is a little kind of too confusing.

While I found that, you can easilly pass as many parameters as you want to every ajax callback using jquery.

Here are two easier solutions.

First one, which @zeroasterisk has mentioned above, example:

var $items = $('.some_class');
$.each($items, function(key, item){
    var url = 'http://request_with_params' + $(item).html();
    $.ajax({
        selfDom     : $(item),
        selfData    : 'here is my self defined data',

        url         : url,
        dataType    : 'json',
        success     : function(data, code, jqXHR){
            // in $.ajax callbacks, 
            // [this] keyword references to the options you gived to $.ajax
            // if you had not specified the context of $.ajax callbacks.
            // see http://api.jquery.com/jquery.ajax/#jQuery-ajax-settings context
            var $item = this.selfDom;
            var selfdata = this.selfData;
            $item.html( selfdata );
            ...
        } 
    });
});

Second one, pass self-defined-datas by adding them into the XHR object which exists in the whole ajax-request-response life span.

var $items = $('.some_class');
$.each($items, function(key, item){
    var url = 'http://request_with_params' + $(item).html();
    $.ajax({
        url         : url,
        dataType    : 'json',
        beforeSend  : function(XHR) {
            // ??????,???? jquery??????? XHR
            XHR.selfDom = $(item);
            XHR.selfData = 'here is my self defined data';
        },
        success     : function(data, code, jqXHR){
            // jqXHR is a superset of the browser's native XHR object
            var $item = jqXHR.selfDom;
            var selfdata = jqXHR.selfData;
            $item.html( selfdata );
            ...
        } 
    });
});

As you can see these two solutions has a drawback that : you need write a little more code every time than just write:

$.get/post (url, data, successHandler);

Read more about $.ajax : http://api.jquery.com/jquery.ajax/

actually, your code is not working because when you write:

$.post("someurl.php",someData,doSomething(data, myDiv),"json"); 

you place a function call as the third parameter rather than a function reference.

You can also try something like the following:

function clicked() {

    var myDiv = $("#my-div");

    $.post("someurl.php",someData,function(data){
        doSomething(data, myDiv);
    },"json"); 
}

function doSomething(curData, curDiv) {

}