Resize window height after window width has resize

Question

Javascript newbie here,

I have this code with a button

<a href="#" onclick="javascript:popoutPlayer();">Popout</a>

Which triggers a window.open call

function popoutPlayer(){
    window.open('popout.html', 'popout', 'width=645, height=363');
}

A new window opens up and I want to resize the window width and when I do I want the width to stay the same, but the height to change to 800

I have been working with this code

<script type="text/javascript">
var rtime = new Date();
var timeout = false;
var delta = 200;

$(window).resize(function() {
    rtime = new Date();
    if (timeout === false) {
        timeout = true;
        setTimeout(resizeend, delta);
    }
});

function resizeend() {
    if (new Date() - rtime < delta) {
        setTimeout(resizeend, delta);
    } else {
        timeout = false;
        //alert('Done resizing');
        var windowWidth = $(window).width();
        var windowHeight = $(window).height();      
        windowHeight = 800;
        window.resizeTo($(window).width(), windowHeight);
    }               
}
</script>

But when the popout, pops out the height changes to 800, but the width gets smaller and small every 200 milliseconds.

What Am I doing wrong?