1.

.find("a/img") doesn't work in FireFox.

2.

$.ajax({url:'a.xml', type:'GET', dataType:'xml', ifModified:true, global:false, timeout:5000, success:function(xml){

var logR = $(xml).find("reads/web").text();

......

doesn't work in FireFox and IE

a.xml:

<logStats>

<reads>

<web>1</web>

<feed>0</feed>

</reads>

</logStats>