If you want to simulate someone clicking on a link, use location.href
If you want to simulate an HTTP redirect, use location.replace
For example:
// similar behavior as an HTTP redirect
window.location.replace("http://stackoverflow.com");
// similar behavior as clicking on a link
window.location.href = "http://stackoverflow.com";
but the code after won't get to execute and the whole page and its context, all will be released.
You need to download the page , parse and extract the information you want from it.
Using jQuery you can simply :
$.get("downlinkPage", function(data, status){
$($.parseHTML(data)).filter('your desire query');
});