validate form OOP JS (L3)

by slawe

HTML

<form id="ourForm">
    <label>First Name</label><input type="text" /><br />
    <label>Last Name</label><input type="text" /><br />
    <label>Email</label><input type="text" /><br />
    <input type="submit" value="submit" />
</form>

JavaScript

addEvent(window, 'load', function() {
    var ourForm = document.getElementById('ourForm');   
    var submit_button = Form.getSubmit('ourForm');
    submit_button.disabled = 'disabled';
     
    function checkForm() {
        var inputs = ourForm.getElementsByTagName('input');
        
        if(Form.validateLength(inputs[0], Form.fname)) {
            if(Form.validateLength(inputs[1], Form.lname)) {
                if(Form.validateEmail(inputs[2])) {
                    submit_button.disabled = false;
                    return true;
                }
            }
        }
             
        submit_button.disabled = 'disabled';
        return false;
    };
     
    checkForm();        
    addEvent(ourForm, 'keyup', checkForm);
    addEvent(ourForm, 'submit', checkForm);
       
     
});

var Form = {
    validClass : 'valid',
     
    fname : {
        minLength : 1,      
        maxLength : 15, 
        fieldName : 'First Name'
    },
     
    lname : {
        minLength : 1,      
        maxLength : 25,
        fieldName : 'Last Name'
    },
 
    validateLength : function(formEl, type){
        if(formEl.value.length > type.maxLength || formEl.value.length < type.minLength ){    
            formEl.className = formEl.className.replace(' '+Form.validClass, '');
            return false;
        } else {
            if(formEl.className.indexOf(' '+Form.validClass) == -1)
            formEl.className += ' '+Form.validClass;
            return true;
        }
    },
 
    validateEmail : function(formEl){
        var regEx = /^([0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*@([0-9a-zA-Z][-\w]*[0-9a-zA-Z]\.)+[a-zA-Z]{2,9})$/;
        var emailTest = regEx.test(formEl.value);        
        
        if (emailTest) {
            if(formEl.className.indexOf(' '+Form.validClass) == -1)         
            formEl.className += ' '+Form.validClass;            
            return true;
        } else {
            formEl.className = formEl.className.replace('...