Validation BackEnd(Client Side) in Joomla

Using following code you can create a client side validation

<script>

  // our validation script

 function doValidate( f )

  {

  if(document.adminForm.task.value == 'gallarycat.cat_cancel')

  {

     return true;

  }

  if( document.formvalidator.isValid( f ) )

    {

                                alert('submit');

                    return true;

    }

    var form = document.adminForm;

    var validator = new myFormValidator();

    if( validator.isValid( form ) )

    {

                 alert("submit");

      submitform( pressbutton );

    }

    else

    {

      alert( 'Please correct any errors before submission.' );

    }

  }

</script>

 

<style type="text/css">

  .invalid { border: 1px solid red; }

</style>

<form action="<?php echo JRoute::_('index.php?option=com_gallary')?>" method="post" name="adminForm" id="adminForm" class="form-validate" onsubmit="return doValidate(this);">

            <input type="text" name="file_name" value="<?=$this->data->file_name;?> " <?php if(isset($this->data->file_name)){echo "readonly"; } ?>  class="required"/>

</form>