firefox cache loses the "disabled" attribute on html tags

<html> 
<head>
	<script type="text/javascript">

	function removeDisabledAttribute(){
		if (confirm("remove disabled attribute?")){
			document.testform.searchbutton.disabled = false;
		}
	}
	</script>
</head>

<body onLoad="removeDisabledAttribute();">

	<form name="testform">
		<input type="text">
		<button type="submit" disabled="disabled" name="searchbutton">Search</button>
	</form>

	<br>
	<a href="http://www.google.com">go to google and come back</a>

</body>
</html>

If you load a form with a submit button set to "disabled", and then some javascript removes the "disabled" attribute, if you ctrl-r refresh the page the disabled attribute is missing from the refreshed page. Here is a minimal repro case. Load the page, note the button is grayed out, when asked "remove disabled attribute?" click "ok", then reload the page, and *don't* remove the disabled attribute. The button should be disabled, but isn't. <br /> <pre><nowiki><html> <head> <script type="text/javascript"> function removeDisabledAttribute(){ if (confirm("remove disabled attribute?")){ document.testform.searchbutton.disabled = false; } } </script> </head> <body onLoad="removeDisabledAttribute();"> <form name="testform"> <input type="text"> <button type="submit" disabled="disabled" name="searchbutton">Search</button> </form> <br> <a href="http://www.google.com">go to google and come back</a> </body> </html></nowiki></pre>