表格验证难度

Question

I am building a form with codeIgniter. I have some required fields in my form and when the required fields are blank the form goes to the same page. What I want to do is that when a required field is empty, it will prompt an alert saying that the fields are required. As I am new to programming I am finding it difficult to do this function. Can any one tell me how can I do this. Thanks. FYI, the other functionality of the form is fine.

Part of my controller:

function index() {
    $this->form_validation->set_rules('address', 'address', 'required');
    $this->form_validation->set_rules('area', 'area', '');
    $this->form_validation->set_rules('lat', 'latitude', 'required');
    $this->form_validation->set_rules('lng', 'longitude', 'required');          
    $this->form_validation->set_rules('subject', 'subject', 'required');
    $this->form_validation->set_rules('problem', 'problem detail', 'required');
    // validation hasn't been passed
    if ($this->form_validation->run() == FALSE) 
    {
        $this->load->view('report_view',$data );
    }
    else // passed validation proceed to post success logic
    {
           ///do something.....
    }

Part of my view:

<?php // Change the css classes to suit your needs    
     $attributes = array('class' => '', 'id' => '');
     echo form_open_multipart('report', $attributes);
?>
<p>
    <br/>
    <label for="address">Address <span class="required">*</span></label>
    <?php echo form_error('address'); ?>
    <br />
    <input id="address" type="text" name="address"
      value="<?php echo  set_value('address'); ?>"  />
</p>

<p>
    <label for="area">Area </label>
    <?php echo form_error('area'); ?>
    <br />
    <input id="area" type="text" name="area"
      value="<?php echo set_value('area'); ?>"  />
</p>

<p>
    <label for="lat">Latitude<span class="required">*</span></label>
    <?php echo form_error('lat'); ?>
    <br />
    <input id="lat" type="text" name="lat"
      value="<?php echo  set_value('lat'); ?>"  />

<p>
    <label for="lng">Longitude<span class="required">*</span></label>
    <?php echo form_error('lng'); ?>
    <br />
    <input id="lng" type="text" name="lng"
      value="<?php echo set_value('lng'); ?>"  />
</p>

<p>
    <label for="subject">Subject:<span class="required">*</span></label>
    <?php echo form_error('subject'); ?>
    <br />
    <input id="subject" type="text" name="subject"
      value="<?php echo set_value('subject'); ?>"  />
</p>

<p>
    <label for="problem">Problem detail:<span class="required">*</span></label>
    <?php echo form_error('problem', '</div>'); ?>
    <br />
    <textarea id="problem" style="width:300px; height:80px"
      type="text" name="problem"><?php echo set_value('problem'); ?>
    </textarea>
</p>

My model:

function SaveForm($form_data)
{
    $this->db->insert('info', $form_data);

    if ($this->db->affected_rows() == '1')
    {
        return TRUE;
    }
    return FALSE;
}

Answer 1

A tested example

Your controller file:

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Welcome extends CI_Controller {

    public function index()
    {
        $this->load->library('session');
        $this->load->helper('url');
        $this->load->library('form_validation');

        if ($this->input->server('REQUEST_METHOD') == 'POST') { // make sure it's post request

            $this->form_validation->set_error_delimiters('', '');

            $this->form_validation->set_rules('address', '<b>address</b>', 'required|xss_clean');
            $this->form_validation->set_rules('area', '<b>area</b>', 'xss_clean');
            $this->form_validation->set_rules('lat', '<b>lat</b>', 'required|xss_clean');
            $this->form_validation->set_rules('lng', '<b>lng</b>', 'required|xss_clean');
            $this->form_validation->set_rules('subject', '<b>subject</b>', 'required|xss_clean');
            $this->form_validation->set_rules('problem', '<b>problem</b>', 'required|xss_clean');

            if ($this->form_validation->run() !== FALSE) { // validation has passed

                // insert the form data into database
                $this->db->insert('info', $form_data);

                // do other stuff

                redirect('/index.php/success-page');
            } else {
                $this->session->set_userdata($this->session->flashdata_key . ':old:error', 'We have some form error. Please review them!');
            }
        }

        $this->load->view('welcome_message');
    }
}

Your view file:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>Welcome to CodeIgniter</title>

    <style type="text/css">

    body {
        background-color: #fff;
        margin: 40px;
        font: 13px/20px normal Helvetica, Arial, sans-serif;
        color: #4F5155;
    }
    </style>
</head>
<body>
    <form method="post">

        <?php if ($this->session->flashdata('error') != '') { ?>
            <?php echo $this->session->flashdata('error');?><br />
        <?php } ?>

        <label>address</label>
        <input type="text" name="address" value="<?php echo set_value('address');?>" /><br />
        <?php if (form_error('address')) { ?><?php echo form_error('address');?><br /><?php } ?>

        <label>area</label>
        <input type="text" name="area" value="<?php echo set_value('area');?>" /><br />
        <?php if (form_error('area')) { ?><?php echo form_error('area');?><br /><?php } ?>

        <label>lat</label>
        <input type="text" name="lat" value="<?php echo set_value('lat');?>" /><br />
        <?php if (form_error('lat')) { ?><?php echo form_error('lat');?><br /><?php } ?>

        <label>lng</label>
        <input type="text" name="lng" value="<?php echo set_value('lng');?>" /><br />
        <?php if (form_error('lng')) { ?><?php echo form_error('lng');?><br /><?php } ?>

        <label>subject</label>
        <input type="text" name="subject" value="<?php echo set_value('subject');?>" /><br />
        <?php if (form_error('subject')) { ?><?php echo form_error('subject');?><br /><?php } ?>

        <label>problem</label>
        <input type="text" name="problem" value="<?php echo set_value('problem');?>" /><br />
        <?php if (form_error('problem')) { ?><?php echo form_error('problem');?><br /><?php } ?>

        <input type="submit" value="Submit">

    </form>
</body>
</html>

Notes:
* use $this->input->server('REQUEST_METHOD') == 'POST' to make sure the form validation runs only on form submit
* if you have a form error don't show another page or redirect, just leave the user on the same page to show the errors