function resizeHandler() {
    var myWidth = 0, myHeight = 0;
    if (typeof (window.innerWidth) == 'number') {
        //Non-IE
        myWidth = window.innerWidth;
        myHeight = window.innerHeight;
    } else if (document.documentElement && (document.documentElement.clientWidth || document.documentElement.clientHeight)) {
        //IE 6+ in 'standards compliant mode'
        myWidth = document.documentElement.clientWidth;
        myHeight = document.documentElement.clientHeight;
    }
    else if (document.body && (document.body.clientWidth || document.body.clientHeight)) {
        //IE 4 compatible
        myWidth = document.body.clientWidth;
        myHeight = document.body.clientHeight;
    }

    if (myHeight <= 720) {
        document.getElementById("tree").style.bottom = 'auto';
        document.getElementById("tree").style.top = '0px';
    }
    else {
        document.getElementById("tree").style.bottom = '0px';
        document.getElementById("tree").style.top = 'auto';
    }
}