Description:
------------
when a tag attribute contains a <, it does not get removed properly.

Reproduce code:
---------------
<?
$s = <<<EOT
nothing should be between this - <img src="http://static.flickr.com/105/253610807_10f90540d3.jpg?v=0" alt="" style="max-width:50px;width:expression(this.width>50?50:true);"></img> - and this.
EOT;
echo($s);
echo('<hr>');
echo('original: '.htmlentities($s));
echo('<hr>');
echo('stripped: '.htmlentities(strip_tags($s)));
?>

Expected result:
----------------
stripped: nothing should be between this -  - and this.

Actual result:
--------------
stripped: nothing should be between this - 50?50:true);"> - and this.