window.onload = initForms;

function initForms() {
    for (var i=0; i< document.forms.length; i++) {
        document.forms[i].onsubmit = function() {return validForm();}
    }
}

function validForm() {
    var allGood = true;
    var allTags = document.getElementsByTagName("*");

    for (var i=0; i<allTags.length; i++) {
        if (!validTag(allTags[i])) {
            allGood = false;
        }
    }
    return allGood;

    function validTag(thisTag) {
        var outClass = "";
        var allClasses = thisTag.className.split(" ");

        for (var j=0; j<allClasses.length; j++) {
            outClass += validBasedOnClass(allClasses[j]) + " ";
        }

        thisTag.className = outClass;

        if (outClass.indexOf("invalid") > -1) {
            thisTag.focus();
            if (thisTag.nodeName == "INPUT") {
                thisTag.select();
            }
            return false;
        }
        return true;

        function validBasedOnClass(thisClass) {
            var classBack = "";

            switch(thisClass) {
                case "":
                case "invalid":
                    break;
                case "reqd":
                    if (allGood && thisTag.value == "") {
                        classBack = "invalid ";
                    }
                    classBack += thisClass;
                    break;
                default:
                    classBack += thisClass;
            }
            return classBack;
        }
    }
}