Client-side form validation

Introduction

Joomla 1.5 contains a behavior JHTMLBehavior::formvalidation() which enables the script validate.js. It uses mootools and allows your form and its elements to be validated.

Note: For more recent versions of Joomla (1.5.2) use JHTML::_('behavior.formvalidation') instead of JHTMLBehavior::formvalidation()

Enable the Validation

The only thing you have to do is set the classes of the form and elements to the specified meanings. Classes:

Form

• form-validate -> enable validation

Form elements

• required
• validate-username
• validate-password
• validate-numeric
• validate-email
• validate-[custom] -> custom handlers have to be set then!

Style Invalid Elements

If some elements don't validate they will get the class

• invalid

If you style the class in the cascading style sheet, your users will be able to see which fields are wrong. For instance:

.invalid {color:red;}

Only Accept the Form After Validation

If you don't want the form to submit anything unless the values are validated, here's a nice script:

<?php JHTMLBehavior::formvalidation(); ?>
<script language="javascript">
function myValidate(f) {
   if (document.formvalidator.isValid(f)) {
      f.check.value='<?php echo JUtility::getToken(); ?>'; //send token
      return true; 
   }
   else {
      var msg = 'Some values are not acceptable.  Please retry.';

      //Example on how to test specific fields
      if($('email').hasClass('invalid')){msg += '\n\n\t* Invalid E-Mail Address';}

      alert(msg);
   }
   return false;
}
</script>
<form id="WV-form" method="post" class="form-validate" onSubmit="return myValidate(this);">
<input type="hidden" name="check" value="post"/>
...
<input type="text" name="email" id="email" size="30"  class="required validate-email"/>
...
<input type="submit" value="Submit" />
</form>

The page that receives the value can check several things:

defined( '_JEXEC' ) or die( 'Restricted access' );  //Verify Joomla enabled
$jAp=& JFactory::getApplication();
if ($_POST['check']!=JUtility::getToken()) {
   // First verify (by a Javascript error or other methods) that the form has not been submitted without the validation
   if ($_POST['check']=='post')	$jAp->enqueueMessage('Please check all the fields of the form, aub.<br/>
If your browser blocks Javascript, then this form will never be successful. This is a security measure.','error');
   // If the check still isn't a valid token, do nothing. This might be a spoof attack or other invalid form submission
   return false;
}

Custom Handlers

If you want a custom handler, you can add one to the class, as in the following example (defined AFTER the validate.js):

Window.onDomReady(function() {
   document.formvalidator.setHandler('birth', function(value) {
      regex=/^\d{4}(-\d{2}){2}$/;
      return regex.test(value);
   })
})

You can then set any class to validate-birth to make it validate as yyyy-mm-dd. (Valid date is not checked!)

Work Around when Using with JToolBar

If you are using JHTML::_('behavior.formvalidation') with JToolBar, for example use in backend, the above method will not work. This is because it depends on onSubmit event which did not fire when we call form.submit via JavaScript. To work around this, we have to move the code in onSubmit to be in submitbutton function override. This will look like this:-

<script type="text/javascript">
/* Override joomla.javascript, as form-validation not work with ToolBar */
function submitbutton(pressbutton) {
    if (pressbutton == 'cancel') {
        submitform(pressbutton);
    }else{
        var f = document.adminForm;
        if (document.formvalidator.isValid(f)) {
            submitform(pressbutton);    
        }
        else {
            var msg = new Array();
            msg.push('Invalid input, please verify again!');
            if ($('title').hasClass('invalid')) {
                msg.push('<?php echo JText::_('COM_JONGMAN_ERROR_SCHEDULE_TITLE_IS_REQUIRED')?>');    
            }
            if($('admin_email').hasClass('invalid')){
                msg.push('<?php echo JText::_('COM_JONGMAN_ERROR_INVALID_EMAIL')?>');
            }
            alert (msg.join('\n'));
        }
    }    
}
</script>