Add Validation using javascript to existing registration form

THIS IS MY CURRENT REGISTRATION SCRIPT AND WOULD LIKE TO IMPLEMENT THE CODE BELOW THIS TO VALIDATE MY FORM
 
$editFormAction = $_SERVER['PHP_SELF'];
if (isset($_SERVER['QUERY_STRING'])) {
  $editFormAction .= "?" . htmlentities($_SERVER['QUERY_STRING']);
}
 
if ((isset($_POST["MM_insert"])) && ($_POST["MM_insert"] == "form1")) {
 
	//validate
	$error = "";
	if($_REQUEST['name'] == "")
		$error.= "enter name,<br>";
	if($_REQUEST['email'] =="")
		$error.="enter email,<br>";
	if($_REQUEST['phone']=="")
		$error.="enter phone,<br>";
	if($error != ""){
		echo "<div class='free'>Please go <a href='register_full.php'>back</a> and<blockquote>".$error."</blockquote></div>";
		include('footer2.php');
		die();
	}
  $password = rand(9898,9898998);
  
  //send member information
  $message = 
'
message body
 
Please keep the following for your records:
 
Username: '.$_REQUEST['email'].'
Password: '.$password;
 //mail member
  @mail($_REQUEST['email'],'Member Registration',$message,'From:'.$settings['email']);
  $mailmessage = '<div align=center class="pageSubTitle">Username and Password sent to '.$_REQUEST['email'].'</div>';
  @mail($settings['email'],'How did you hear about us',$_REQUEST['hear_about'],'From:email@email.com');
  $insertSQL = sprintf("INSERT INTO members (name, address, city, `state`, zip, active, email, password, phone) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s)",
                       GetSQLValueString($_POST['name'], "text"),
                       GetSQLValueString($_POST['address'], "text"),
                       GetSQLValueString($_POST['city'], "text"),
                       GetSQLValueString($_POST['state'], "text"),
                       GetSQLValueString($_POST['zip'], "text"),
                       GetSQLValueString($_POST['active'], "text"),
                       GetSQLValueString($_POST['email'], "text"),
                       GetSQLValueString($password, "text"),
                       GetSQLValueString($_POST['phone'], "text"));
 
  mysql_select_db($database_myconn, $myconn);
  $Result1 = mysql_query($insertSQL, $myconn) or die(mysql_error());
  $result2 = mysql_query("SELECT LAST_INSERT_ID() as autoId") or die(mysql_error());
  $auto = mysql_fetch_assoc($result2);
  mysql_query("UPDATE members SET groupid=". $auto['autoId']." WHERE id=" . $auto['autoId'] . " LIMIT 1") or die(mysql_error());
	
  echo "<h3><font color=red>You are now registered, check your email for username and password</font></h3>        
 <a href='login.php' class='pageLink'>Sign In</a>";
  $message =
  'A new user has signed up to '.$settings['domain'].'
  
  Member Info: 
  '.$_REQUEST['name'].'
  '.$_REQUEST['phone'].'
  '.$_REQUEST['email'].'
  
  ';
  
   mail($settings['email'],"New Registered User",$message,"FROM:".$settings['email']);
}
?>
 
________________________________________________________________________
THIS IS THE JAVASCRIPT VALIDATION I WOULD LIKE TO IMPLEMENT HOWEVER IT DOES NOT GET TRIGGERED WHEN I CHANGE THE FORM TO NAME
function checkForm()
{
   var cname, cemail, cpassword, cpassword2;
   with(window.document.msgform)
   {
      cname    = name;
      cemail   = email;
      cpasswword = password;
      cpassword2 = password2;
   }
 
   if(trim(cname.value) == '')
   {
      alert('Please enter your name');
      cname.focus();
      return false;
   }
   else if(trim(cemail.value) == '')
   {
      alert('Please enter your email');
      cemail.focus();
      return false;
   }
   else if(!isEmail(trim(cemail.value)))
   {
      alert('Email address is not valid');
      cemail.focus();
      return false;
   }
   else if(trim(cpassword.value) == '')
   {
      alert('Please enter a password');
      cphone.focus();
      return false;
   }
   else if(trim(cpassword2.value) == '')
   {
      alert('Please re-enter a password');
      cpassword.focus();
      return false;
   }
   else
   {
      cname.value    = trim(cname.value);
      cemail.value   = trim(cemail.value);
      cpassword.value = trim(cpassword.value);
      cpassword2.value = trim(cpassword2.value);
      return true;
   }
}
 
function trim(str)
{
   return str.replace(/^\s+|\s+$/g,'');
}
 
function isEmail(str)
{
   var regex = /^[-_.a-z0-9]+@(([-_a-z0-9]+\.)+(ad|ae|aero|af|ag|
ai|al|am|an|ao|aq|ar|arpa|as|at|au|aw|az|ba|bb|bd|be|bf|bg|
bh|bi|biz|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|
ch|ci|ck|cl|cm|cn|co|com|coop|cr|cs|cu|cv|cx|cy|cz|de|dj|dk|
dm|do|dz|ec|edu|ee|eg|eh|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|
gd|ge|gf|gh|gi|gl|gm|gn|gov|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|
hr|ht|hu|id|ie|il|in|info|int|io|iq|ir|is|it|jm|jo|jp|ke|kg|
kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|
ma|mc|md|mg|mh|mil|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|museum|
mv|mw|mx|my|mz|na|name|nc|ne|net|nf|ng|ni|nl|no|np|nr|nt|nu|
nz|om|org|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|pro|ps|pt|pw|py|qa|
re|ro|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl|sm|sn|so|sr|st|
su|sv|sy|sz|tc|td|tf|tg|th|tj|tk|tm|tn|to|tp|tr|tt|tv|tw|tz|
ua|ug|uk|um|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|yu|za|
zm|zw)|(([0-9][0-9]?|[0-1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5])\.){3}([0-9][0-9]?|[0-1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5]))$/i;
 
return regex.test(str);
}