function height_detect(from_top){
    var dheight = document.getElementById('body_text').clientHeight;
    var totalHeight = parseInt(dheight)+parseInt(from_top);
    
    if(totalHeight<800)
    {
        var newHeight = 800-parseInt(from_top);
        document.getElementById('body_text').style.height = newHeight+"px";
        document.getElementById('body_text').style.top = parseInt(from_top)+"px";
        var padding = 20;
        var superHeight = newHeight+parseInt(from_top)+parseInt(padding);
        document.getElementById('bottom_bar').style.top = superHeight+"px";
    }
    else
    {
        document.getElementById('bottom_bar').style.top = totalHeight+"px";
    }
}