function trim(stringToTrim) 
    {
	    return stringToTrim.replace(/^\s+|\s+$/g,"");
    }
    function ltrim(stringToTrim) 
    {
	    return stringToTrim.replace(/^\s+/,"");
    }
    function rtrim(stringToTrim) 
    {
	    return stringToTrim.replace(/\s+$/,"");
    }

    function validate_form ( )
    {
        var tb = document.getElementById("EmailTextBox");
        if (trim(tb.value) == "" || tb.value.indexOf("@") == -1 || tb.value.indexOf(".") == -1)
        {
            var valSpan = document.getElementById("ValidationMessage");
            valSpan.innerHTML = "Please enter a valid email address.";
            valSpan.style.display="block";
            return false;
        }
        return true;
    }