Perfect Javascript Form Validation using Regular Expressions.

I had designed a perfect form validation using javascript regular expression. Simple code and works perfect in all conditions. It's very useful and supporting all the web browsers just take a look at post. 

Name:
Alphabets, numbers and space(' ') no special characters min 3 and max 20 characters.

var ck_name = /^[A-Za-z0-9 ]{3,20}$/;

Learning JavaScript, 2nd Edition

Email
Standard email address 

var ck_email = /^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i

UserId
Supports alphabets and numbers no special characters except underscore('_') min 3 and max 20 characters. 

var ck_username = /^[A-Za-z0-9_]{3,20}$/;

Password
Password supports special characters and here min length 6 max 20 charters.

var ck_password = /^[A-Za-z0-9!@#$%^&*()_]{6,20}$/;

JavaScript Code:
You have to include this code within the tag HEAD of the page. 

<script type="text/javascript">
var ck_name = /^[A-Za-z0-9 ]{3,20}$/;
var ck_email = /^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]
{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i 
var ck_username = /^[A-Za-z0-9_]{1,20}$/;
var ck_password =  /^[A-Za-z0-9!@#$%^&*()_]{6,20}$/;

function validate(form){
var name = form.name.value;
var email = form.email.value;
var username = form.username.value;
var password = form.password.value;
var gender = form.gender.value;
var errors = [];
 
 if (!ck_name.test(name)) {
  errors[errors.length] = "You valid Name .";
 }
 if (!ck_email.test(email)) {
  errors[errors.length] = "You must enter a valid email 
address.";
 }
 if (!ck_username.test(username)) {
  errors[errors.length] = "You valid UserName no special 

char .";
 }
 if (!ck_password.test(password)) {
  errors[errors.length] = "You must enter a valid Password ";
 }
 if (gender==0) {
  errors[errors.length] = "Select Gender";
 }
 if (errors.length > 0) {

  reportErrors(errors);
  return false;
 }
  return true;
}
function reportErrors(errors){
 var msg = "Please Enter Valide Data...\n";
 for (var i = 0; i<errors.length; i++) {
 var numError = i + 1;
  msg += "\n" + numError + ". " + errors[i];
}
 alert(msg);
}
</script>

HTML Code
You have to modify action="#"

<form method="post" action="#" onSubmit="return validate(this);" name="form">

</form>