<?php

$string = "<td class=x11111111111111111 width=140 style='>1111111111111111111111111111<td>11111111111111border-top:none;border-left:none; width:107pt'>";

$doc = new DOMDocument(); 
$doc->loadHTML($string, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);    
$elements = $doc->getElementsByTagName('td'); 

foreach ($elements as $element) {
	$attributes = $element->attributes;
	while ($attributes->length) {
        $element->removeAttributeNode($attributes->item(0));
    }
} 
echo $doc->saveHTML(); 