Detect when JavaScript has finished executing...

**misha680** · 05-20-2010 04:14 PM

Is there a way to detect when the result of a JavaScript script have finished executing.

For example, if I have a (browser-side) Javascript function that fills in a text field, or submits a form, how do I know when the page is finished changing?

Again my only idea is to check the whole DOM tree with setInterval... but this seems quite tedious.

Any better solutions?

Thank you
Misha

**justinbarneskin** · 05-20-2010 08:25 PM

Its the return true statement of the function that signals its completion

HTML Code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
	"http://www.w3.org/TR/html4/strict.dtd">
<HTML>
<HEAD><TITLE>Th6-21pm52</TITLE>
<META http-equiv=Content-Type content="text/html; charset=UTF-8">
<STYLE type=text/CSS>


</STYLE>
<SCRIPT type="text/javascript">
function myFunction(){
for(i=0;i<document.forms[0].elements.length;i++){document.forms[0].elements[i].value=i}
return true
}
</SCRIPT>
<META content="MSHTML 6.00.2900.2963" name=GENERATOR></HEAD>
<BODY scroll="auto" onload="if(myFunction()){alert('done')}">
<form>
<input><input><input><input><input>
</form>

</BODY></HTML>

**misha680** · 05-21-2010 10:15 AM

Thank you. I guess let me be more specific.

I am on the client (browser side).

I execute a Javascript (say one that launches events).

Sometimes, this Javascript, for example, causes a new page to load, or causes new DOM elements to be created (clicking on the "Check" menu in Google Voice, or posting a Wall Post on Facebook).

I would like to know when all the _consequences_ of running my script have completed.

My simple idea:
* look at document.getElementsByTagName('*').length every 2 seconds (?)
* if it has not changed - we are done. otherwise, wait again

What do you think?

Misha

**justinbarneskin** · 05-21-2010 10:54 AM

If I knew how to write a loop that would take many seconds to run,
the return would not return until the code is finished running.
I stand by my earlier example.
Perhaps you missed the crucial bit-
if(myFunction()){alert('done')}

**misha680** · 05-21-2010 11:11 AM

Perhaps you are correct.

My challenge is actually to find whether my Javascript caused any DOM changes, and the only cross-browser way I believe to do this is to do a for loop that scans all elements...

Unless you have other suggestions.

Thank you
Misha

**justinbarneskin** · 05-21-2010 04:09 PM

You'll need to post your code before anyone can show a better way to do it.

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