Usage:
var dim = Position.GetWindowSize();
dim[0] is the window width
dim[1] is the window height

window can be specified, useful if you work with frames..

Position.GetWindowSize = function(w) {
        w = w ? w : window;
        var width = w.innerWidth || (w.document.documentElement.clientWidth || w.document.body.clientWidth);
        var height = w.innerHeight || (w.document.documentElement.clientHeight || w.document.body.clientHeight);
        return [width, height]
}

// This could be used for a 9-piece button or window

    <class name="stretchybutton" pixellock="true">
        <resizeview_x name="top" width="100%" 
            left="btn_tl"
            middle="btn_t"
            right="btn_tr" />
        <resizeview_x name="middle" width="100%" 
            left="btn_l"
            middle="btn_m"
            right="btn_r" />
        <resizeview_x name="bottom" width="100%" 
            left="btn_bl"
            middle="btn_b"
            right="btn_br" />
    
        <stableborderlayout axis="y"/>
    class>