Try this:
function doCheck(str1,str2) {
top.LocalCacheLoadStatus = false;
parent.SearchFrame.location.href=str1;
g_str_Mode = str2;
alert (g_str_Mode);
var url = str1+".jsp?str2="+str2;
alert(url);
document.location = url;
}
If you need to pass the variable to the jsp page, and you don't need your user to ever see the output from that jsp page--that is, you want the user to stay on the current page without noticing the value was submitted, you can use a hidden iframe--and navigate it instead of your main page. You can also use an AJAX solution, but an iframe does just fine and is easier to make compatible across browsers.
Unsolved 
