I want to run a function when the page is loaded, but I don’t want to use it in the <body> tag.
I have a script that runs if I initialise it in the <body>, like this:
function codeAddress() {
// code
}
<body onLoad="codeAddress()">
But I want to run it without the <body onload="codeAddress()"> and I have tried a lot of things, e.g. this:
window.onload = codeAddress;
But it is not working.
So how do I run it when the page is loaded?
This question is related to
javascript
html
onload
window.onload = function() { ... etc. is not a great answer.
This will likely work, but it will also break any other functions already hooking to that event. Or, if another function hooks into that event after yours, it will break yours. So, you can spend lots of hours later trying to figure out why something that was working isn't anymore.
A more robust answer here:
if(window.attachEvent) {
window.attachEvent('onload', yourFunctionName);
} else {
if(window.onload) {
var curronload = window.onload;
var newonload = function(evt) {
curronload(evt);
yourFunctionName(evt);
};
window.onload = newonload;
} else {
window.onload = yourFunctionName;
}
}
Some code I have been using, I forget where I found it to give the author credit.
function my_function() {
// whatever code I want to run after page load
}
if (window.attachEvent) {window.attachEvent('onload', my_function);}
else if (window.addEventListener) {window.addEventListener('load', my_function, false);}
else {document.addEventListener('load', my_function, false);}
Hope this helps :)
As soon as the page load the function will be ran:
(*your function goes here*)();
Alternatively:
document.onload = functionName();
window.onload = functionName();
Taking Darin's answer but jQuery style. (I know the user asked for javascript).
$(document).ready ( function(){
alert('ok');
});?
Rather than using jQuery or window.onload, native JavaScript has adopted some great functions since the release of jQuery. All modern browsers now have their own DOM ready function without the use of a jQuery library.
I'd recommend this if you use native Javascript.
document.addEventListener('DOMContentLoaded', function() {
alert("Ready!");
}, false);
Try readystatechange
document.addEventListener('readystatechange', () => {
if (document.readyState == 'complete') codeAddress();
});
where states are:
DOMContentLoadedwindow.onload<script>_x000D_
document.addEventListener("DOMContentLoaded", () => {_x000D_
mydiv.innerHTML += `DOMContentLoaded (timestamp: ${Date.now()})</br>`;_x000D_
});_x000D_
_x000D_
window.onload = () => {_x000D_
mydiv.innerHTML += `window.onload (timestamp: ${Date.now()}) </br>` ;_x000D_
} ;_x000D_
_x000D_
document.addEventListener('readystatechange', () => {_x000D_
mydiv.innerHTML += `ReadyState: ${document.readyState} (timestamp: ${Date.now()})</br>`;_x000D_
_x000D_
if (document.readyState == 'complete') codeAddress();_x000D_
});_x000D_
_x000D_
function codeAddress() {_x000D_
mydiv.style.color = 'red';_x000D_
}_x000D_
</script>_x000D_
_x000D_
<div id='mydiv'></div>window.onload will work like this:
function codeAddress() {_x000D_
document.getElementById("test").innerHTML=Date();_x000D_
}_x000D_
window.onload = codeAddress;<!DOCTYPE html>_x000D_
<html>_x000D_
<head>_x000D_
<title>learning java script</title>_x000D_
<script src="custom.js"></script>_x000D_
</head>_x000D_
<body>_x000D_
<p id="test"></p>_x000D_
<li>abcd</li>_x000D_
</body>_x000D_
</html>Take a look at the domReady script that allows setting up of multiple functions to execute when the DOM has loaded. It's basically what the Dom ready does in many popular JavaScript libraries, but is lightweight and can be taken and added at the start of your external script file.
Example usage
// add reference to domReady script or place
// contents of script before here
function codeAddress() {
}
domReady(codeAddress);
Alternate solution. I prefer this for the brevity and code simplicity.
(function () {
alert("I am here");
})();
This is an anonymous function, where the name is not specified. What happens here is that, the function is defined and executed together. Add this to the beginning or end of the body, depending on if it is to be executed before loading the page or soon after all the HTML elements are loaded.
Source: Stackoverflow.com