Ok, here's my suggestion. If you want to grab just a piece of content from the page, you can use an ajax call, storage the answer inside a variable and use the split jquery function. Lets say that the page that you want to load is a series of divs, inside the div that you want you can place something like at the begining and at the end of the div, after that the rest will be easy, when you get your data from the ajax call you use something like:
var answer = (you ajax response) ;
var content = answer.split("<!-- SPLIT CONTENT -->");
$('#MyCoolContainer').html(content[1]);
By doing this, you'll split the answer in 3 parts, the first one content[0] will be everything before the first comment, content[1] will be the content of the div you want, and content[2] will be everything after the closing SPLIT CONTENT. then you just place that content inside a div.