Website Waters 3 - Contact From Validation - containBlanks function

<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript">
var $submit = $(".submit input");
var $required = $(".required");

    function containsBlanks(){
        var blanks = new Array();
        $required.each(function(){
            blanks.push($(this).val() == "");
        });
        return blanks.sort().pop();
    }

    function isValidEmail(email){
        return email.indexOf("@") != -1;
    }

    function requiredFilledIn (){
        if(containsBlanks())
            $submit.attr("disabled","disabled");
        else
            $submit.remove.attr("disabled");
    }

    $("#form span").hide();
    $("input,textarea").focus(function(){
        $(this).next().fadeIn("slow");
    }).blur(function(){
        $(this).next().fadeOut("slow");
    }).keyup(function(){
        //Check all required fields.
    });

    $("#email").keyup(function(){
        // check for valid email.
        if(isValidEmail($(this).val()))
            $(this).next().removeClass("error").addClass("valid");
        else 
            $(this).next().removeClass("valid").addClass("error");
    });

    requiredFilledIn ();

</script>