Sayler91,
<!DOCTYPE html>
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
</head>
<body>
<table>
<tr>
<th>Обращение:</th>
<td>
<span id="Who" xmlpathvalue="//Information/Who">Мама</span></td>
<td>
<span id="_Who" class="PrintFill" xmlpathvalue="//New_Information/Who">МАМА</span></td>
</tr>
</table>
<input name="" type="button" value="test" onclick="test();">
<script>
function test() {
var a=document,b=a.getElementById("Who"),a=a.getElementById("_Who");
a.style.backgroundColor=b.textContent.toLowerCase()==a.textContent.toLowerCase()?"green":"red";
}
</script>
</body>
</html>