Simple Form Validation

All this does is check to see if the form fields with the class of "required" have values selected / inputted.

The submit button should be:

unction getElementsByClass(searchClass, node, tag)
{
 var classElements = new Array();
 if ( node == null ) node = document;
 if ( tag == null ) tag = '*';
 var els = node.getElementsByTagName(tag);
 var elsLen = els.length;
 var pattern = new RegExp("(^|\\s)"+searchClass+"(\\s|$)");
 for (i = 0, j = 0; i < elsLen; i++)
 {
  if ( pattern.test(els[i].className) )
  {
   classElements[j] = els[i];
   j++;
  }
 }
 return classElements;
}

function check( formName )
{
 var req = getElementsByClass('required', formName.form);
 var err = new Array();
 
 for( var i=0; i < req.length; i++)
 {
  var value = document.getElementById(req[i].htmlFor).value;
  if( value == null || value == '' )
  {
   err.push(req[i].htmlFor);
  }
 }
 
 if( err.length > 0 )
 {
  var txt = 'Please fill in the following fields:' + "\n-" + err.join("\n-");
  alert( txt );
  return false;
 }
 else
 {
  formName.form.submit();
  return true;
 }
}