javascript redirect won't work?

Question

I have a little bit of javascript code that is getting some parameters from php. the php variable $rid is an integer with a value within 1-100. what i am trying to do is change the value of the 'rid' variable in the querystring by a specified amount (offset). when i remove the last str($rid) characters from window.location.href , i am left with http://www.qwerty.asdf/uiop?rid= . When I add <?php echo $rid;?>+offset to it I get http://www.qwerty.asdf/uiop?rid=2 for example. when I try the code, nothing happens, but I've debugged and str is the desired value by the time I say window.location.href=str;

why doesnt the page redirect? I have tried window.location as opposed to window.location.href, but it doesn't work.

ps there is no other javascript on the page

function moveRid(offset) {
    str = window.location.href.substring(0,window.location.href.length-<?php echo strlen($rid);?>);
    rid = <?php echo $rid;?>+offset;
    str += rid;
    window.location.href=str;
}

Answer 1

You need to actually set the window.location

function moveRid(offset) {
    str = window.location.href.substring(0,window.location.href.length-<?php echo strlen($rid);?>);
    rid = <?php echo $rid;?>+offset;
    str += rid;
    //window.location.href=str;
    window.location = str;
}