I want to write an application that detects when a page is loaded in the browser, then I should be able to insert content on top of the loaded web page? Anybody with an idea on how to do that?
Please note that I should be able to do this in any browser (Firefox/IE).
What language should I use to help me do this?
How do I detect this from an external application?
How should I integrate this with the browser?
In Javascript, you have the onload event.
Edit: an example:
<html>
<head>...</head>
<body onload="doSomethingWhenPageIsLoaded();">
...
</body>
</html>
Javascript's OnLoad event for the body does what you want.
<body onload="...">
Javascript using the onLoad() event, will wait for the page to be loaded before executing.
<body onload="somecode();" >
If you're using the jQuery framework's document ready function the code will load as soon as the DOM is loaded and before the page contents are loaded:
$(document).ready(function() {
// jQuery code goes here
});
You would use javascript to do this. If you don't know how to use javascript, I would recommend reading through some tutorials first.
After you have a basic understanding of javascript, you can detect when a page has loaded by using the window.onload event.
window.onload = function() {
addPageContents(); //example function call.
}
Edit: If you want to add more than one onload function, and not use a javascript library, you can wrap your own onload hanlder.
window.whenloaded = function(fn) {
if (window.onload) {
var old = window.onload;
window.onload = function() {
old();
fn();
}
} else {
window.onload = fn;
}
}
Better than onload is to use a function of an existing framework, because onload does sometimes respond after all the resources (images and so on) are loaded and not only the page.
For example jQuery:
$(document).ready( function() {
// do stuff
}
Why not use listeners?
// Everything but IE
window.addEventListener("load", function() {
// loaded
}, false);
// IE
window.attachEvent("onload", function() {
// loaded
});
This way you can add as many Listeners as you want, you can also detach them! removeEventListener and detachEvent.