Why is this invalid html?

redrabbit

I receive 1 error for my validation of HTML 4.01. the code is shown below:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/1999/REC-html401-19991224/loose.dtd">
<html>	    

<head>
<script type="text/javascript" src="funcs.js"></script>

<script type="text/javascript"><!--	
	thisPageId = "viewer";
	pageType = "text";

var stPathRelease = "/";					
var strPathImageFiles = "/";
var strPathVideoFiles = "/";
var strPathAudioFiles = "/";
var strPathTranscriptFiles = "/";
var strPathInterfaceImages = "/";

function writeTag() {
	var str = '';
	[b][color=red]var str = '<iframe id="iframeAudioNow" width="0" height="0" class="audio" frameborder="0" scrolling="no" src="about:blank" title="Ignore this"></iframe>';[/color][/b]
	return str;
}
//--></script>

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>xxxxx</title>
<meta name="keywords" content="">
<meta name="description" content=""> 

<link href="style.css" rel="stylesheet" type="text/css">

<style type="text/css">
<!--
#mainLeft a:link {
	text-decoration: none;

}
#mainLeft a:visited {
	text-decoration: none;

}
#mainLeft a:hover {
	text-decoration: none;

}
-->

</style><style type="text/css"><!--
-->
</style>
<script type="text/javascript" src="include/browserobject.js"></script>
<script type="text/javascript" src="include/navigationobject.js"></script>
<script type="text/javascript" src="include/tracking.js"></script>
<script type="text/javascript" src="include/tabmanager.js"></script>
<script type="text/javascript" src="include/library.js"></script>
<script type="text/javascript" src="include/preloads.js"></script>

</head>
<body>

The line

var str = '<iframe id="iframeAudioNow" width="0" height="0" class="audio" frameborder="0" scrolling="no" src="about:blank" title="Ignore this"></iframe>';

Is seen as invalid, and produces this error:

error from validation wrote:
...t:blank" title="Ignore this"></iframe>';

The Validator found an end tag for the above element, but that element is not currently open. This is often caused by a leftover end tag from an element that was removed during editing, or by an implicitly closed element (if you have an error related to an element being used where it is not allowed, this is almost certainly the case). In the latter case this error will disappear as soon as you fix the original problem.

If this error occured in a script section of your document, you should probably read this FAQ entry.

Any ideas why this errors. If I remove the line it validats fine, so it is definetly this line. No other tags are open.

xblue

redrabbit wrote:
If this error occured in a script section of your document, you should probably read this FAQ entry.

Well, what does the FAQ entry say? Maybe something like

"As mentioned in the HTML 4 Recommendation's note about specifying non-HTML data in element content, end tags are recognized within SCRIPT elements, but other kinds of markup--such as start tags and comments--are not. This is an unintuitive quirk of SGML for elements defined to have CDATA content.

Authors should avoid using strings such as "</P>" in their embedded scripts. In JavaScript, authors may use a backslash to prevent the string from being parsed as markup: