How To Use Multiple Onload Actions on the Same Page

Web applications like FileChucker and UserBase often need to perform tasks that happen after a web page has finished loading.  The traditional way to do this is to add onload="somefunc();" to the page's <body> tag.  But what if you need multiple events to happen at onload time?

To schedule multiple onload events, add the following code to the <head> section of your page: 

<script type="text/javascript">
function schedule_onload_action(newfunc)
{
	var already_scheduled = window.onload;
	if(typeof window.onload != 'function')
	{
		window.onload = newfunc;
	}
	else
	{
		window.onload = function()
		{
			already_scheduled();
			newfunc();
		}
	}
}
</script>

Then take the code that was in your onload="" attribute and add it to a new Javascript function.  For example, if you previously had this: 

<body onload="somefunc('foo', 'bar', 'baz')">

...then you'd replace that with simply "<body>", and create the following new Javascript code in your page's <head> section: 

<script type="text/javascript">
function do_somefunc()
{
	somefunc('foo', 'bar', 'baz');
}
schedule_onload_action(do_somefunc);
</script>

And of course, the whole point is that you can then include as many calls to the schedule_onload_action() function as you wish: 

<script type="text/javascript">
schedule_onload_action(do_somefunc);
schedule_onload_action(do_something_else);
schedule_onload_action(do_that_other_thing);
</script>