function showPopup(selector, layer)
{
    var left = ($(window).width() - $(selector).width()) / 2 + $(window).scrollLeft() - 22;
    var top = ($(window).height() - $(selector).height()) / 2 + $(window).scrollTop() - 22;
    if (left < 0)
    {
        left = 0;
    }
    if (top < 0)
    {
        top = 0;
    }
    $(selector).css({'left' : left + "px"});
    $(selector).css({'top' : top + "px"});
    $(layer).show();
    $(selector).show();
}

function hidePopup(selector, layer)
{
    $(selector).hide();
    $(layer).hide();
}

function isNumeric(e)
{
    var key = '';
    if (window.event)
    {
        key = window.event.keyCode;
    }
    else if (e)
    {
        key = e.which;
    }
    else
    {
        key = null;
    }
    if ((key > 47 && key < 58) || key == 8 || key == 0)   // 0 to 9 and
    {
        return true;
    }
    else
    {
        return false;
    }
}

function isAlphaNumeric(e, withSpace)
{
    var key = '';    
    if (window.event)
    {
        key = window.event.keyCode;
    }
    else if (e)
    {
        key = e.which;
    }
    else
    {
        key = null;
    }
    //console.log(key);
    if ((key > 47 && key < 58) || (key > 64 && key < 91) || (key > 96 && key < 123) || key == 8 || key == 0) // 0 to 9, a to z and A to Z
    {
        return true;
    }
    else if(withSpace === true && key == 32)
    {
        return true;
    }
    else
    {
        return false;
    }
}