<!-- 
    // isEmail (STRING s [, BOOLEAN emptyOK])
    // whitespace characters
    var whitespace = " \t\n\r";
    
    // 
    // Email address must be of form a@b.c ... in other words:
    // * there must be at least one character before the @
    // * there must be at least one character before and after the .
    // * the characters @ and . are both required
    function isValidEmail(s)
    {   
        if (isEmpty(s)) return false;
       
        // is s whitespace?
        if (isWhitespace(s)) return false;
            
        // there must be >= 1 character before @, so we
        // start looking at character position 1 
        // (i.e. second character)
        var i = 1;
        var sLength = s.length;
    
        // look for @
        while ((i < sLength) && (s.charAt(i) != "@"))
        { i++
        }
    
        if ((i >= sLength) || (s.charAt(i) != "@")) return false;
        else i += 2;
    
        // look for .
        while ((i < sLength) && (s.charAt(i) != "."))
        { i++
        }
    
        // there must be at least one character after the .
        if ((i >= sLength - 1) || (s.charAt(i) != ".")) return false;
        else return true;
    }
    
    // Check whether string s is empty.
    function isEmpty(s)
    {   
        return ((s == null) || (s.length == 0))
    }
    
    // Returns true if string s is empty or 
    // whitespace characters only.
    function isWhitespace(s)
    {   
        var i;
    
        // Is s empty?
        if (isEmpty(s)) return true;
    
        // Search through string's characters one by one
        // until we find a non-whitespace character.
        // When we do, return false; if we don't, return true.
        for (i = 0; i < s.length; i++)
        {   
            // Check that current character isn't whitespace.
            var c = s.charAt(i);
    
            if (whitespace.indexOf(c) == -1) return false;
        }
        // All characters are whitespace.
        return true;
    }
    
    function checkForm() { 
        if (!isValidEmail(document.subscribeForm.elements['Email Address'].value)) {
        document.subscribeForm.elements['Email Address'].style.backgroundColor='yellow';
            alert("Please enter a valid Email Address. (name@host.com)");
            document.subscribeForm.elements['Email Address'].focus();
            return false;
        }
    }
    //-->// JavaScript Document