$doc=new DOMDocument(); 
 $doc->loadHTML($str);  
 $doc->getElementById("MainTable")->getAttribute("id");

Displays the error

Fatal error: Call to a member function getAttribute() on a non-object

Oh and $str is the HTML of a page :p

D: Am I doing something wrong? :o

Didn't get your logic.
You are searching from id and want id of searched field ??

Didn't get your logic.
You are searching from id and want id of searched field ??

-facepalm-
I was isolating parts from the rest of the code to see which part wasn't working. And in order for it to actually do something, I just put that there.

LOL XD I found the problem :3 The page I was grabbing (to view its source code) was redirecting to something else :p