function isUrl(value) {
 //   if (value.match(/(http|ftp|https):\/\/[\w\-_]+(\.[\w\-_]+)+([\w\-\.,@?^=%&:/~\+#]*[\w\-\@?^=%&/~\+#])?/)) 
    if ((value.match(/(http|ftp|https):\/\/[\w\-_]+(\.[\w\-_]+)+([\w\-\.,@?^=%&:/~\+#]*[\w\-\@?^=%&/~\+#])?/)) && ((value.substring(7,0).toLowerCase()=="http://") || (value.substring(8,0).toLowerCase()=="https://")))
    {
        return true;
    } else {
        return false;
    }
}
// /(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/

function ExecuteShowPreview(e) {

    if (e) {
        e = e
    } else {
        e = window.event
    }

    if (e.which) {
        var keycode = e.which
    } else {
        var keycode = e.keyCode
    }

    if (keycode == 13) {
        ShowPreview(document.getElementById('url').value);

    }
}

function ShowHideLayer(Layer) {
    el = document.getElementById(Layer);
    el.style.visibility = (el.style.visibility == "visible") ? "hidden" : "visible";
}

function addLoadEvent(func) {
    //http://haacked.com/archive/2006/04/06/StopTheWindow.OnloadMadness.aspx 
    var oldonload = window.onload;
    if (typeof window.onload != 'function') {
        window.onload = func;
    }
    else {
        window.onload = function() {
            oldonload();
            func();
        }
    }
}