Parsing JSON data from ajax call

Question

I have posted a few questions previously on how to do the same thing, and people have pointed me in the right direction. So my apologies if this is getting repetitive. However I am posting this time to see if someone could spare a couple of seconds to help me with javascript.

I have a form that already submits data into a different table, and want to implement a "pre-canned response feature". This would simply be a drop list selection that when the onChange event fires of an option list it runs the javascript that populates a following text area with appropriate data.

I believe as it is already in a form, I can't simply put it in another form and use submit, also, I want to be able to do this without refreshing the page.`

<form action="<?=base_url();?>ticket/addmessage/<?=$ticket_details['id'];?>/" enctype="multipart/form-data" method="post" name="message">

        <label for="frm_precan">Canned Response</label>
        <span class="input">                        
            <select id="frm_precan" name="precan" onchange="updateText()">
                <option value="">--Please Select--</option>
                <?php foreach($precan_list as $precan) :?>
                    <option value="<?=$precan['id']; ?>"><?=$precan['name'];?></option>
                <?php endforeach; ?>            
            </select>
        </span>

        <ul>
            <li><label for="message">Message<span class="req">*</span></label><span class="input"></span><br/></li> 
        </ul>   
        <textarea style="width: 100%; margin: 0; padding: 0; border-width: 1; font-family: courier;" name="message" rows="10" id="text_area"></textarea>
        <button type="submit"><span>Add Message</span></button>

</form>

This is my HTML form. It uses PHP via SQL to populate the option list, as the pre-canned messages are stored in SQL table.

So what I need to do is somehow link this Javascript (that is called on the onChange):

        function updateText()
       {
       var message = document.getElementById('frm_precan').value;
       $('#text_area').val(message)
       };

(very basic, I know, but this is where I struggle) So this code wants to pass the ('frm_precan').value; (which is the ID in the table, and the field by which I want to query the correct message)... to a php file that looks like this:

    public function get_message($message_id)
    {
        $sql_list  =
        "
        SELECT *
        FROM  ".$this->tables_automessages."
        WHERE id = '".mysql_real_escape_string($message_id)."'";

        $query = $this->db->query($sql_list);
        if($query->num_rows() > 0)
            {
            foreach ($query->result_array() as $row)
                {
                $return[] =
                array(
                        'message'                   =>  $row['message']

                    );
                }
            return $return;
            }
        else return false;
        }
}

O, and I am using code ignitor, so this could also be a reason why I am getting confused. So the variable wants to come out of the javascript into a controller then go to the SQL query.

If someone can understand what I mean, I will be amazed... and very grateful.

What's the problem you're having? (it might be that your return statement in your PHP is inside the for loop, that looks a little odd). — alnorth29
– alnorth29, Commented Jul 6, 2012 at 11:05
The problem I have is using the javascript. I have posted a very basic bit of javascript, as I am not very confident with javascript. I just need help with making it work something like what I've seen on various tutorials......e.g. w3schools.com/php/php_ajax_database.asp — Mr Sorbose
– Mr Sorbose, Commented Jul 6, 2012 at 11:10
@alnorth29: the return statement isn't inside the loop, it's where it needs to be. @mrsorbose: I see nothing ajax-like in your code anywhere, though. You might want to look at jQuery's (as you seem to use it already) $.ajax method. Also, if it's a separate script (ie not a class), get_message will be a standard function, not a member function/method, so drop the public keyword — Elias Van Ootegem
– Elias Van Ootegem, Commented Jul 6, 2012 at 11:14

davidethell · Accepted Answer · 2012-07-06 11:10:31Z

2

Your updateText function can be changed to this to get the value from your controller and put the resulting text in the text area.

function updateText()
{
    var messageId = $('#frm_precan').val();
    $.get('/yourcontroller/get_message/' + messageId, function(data) {
        $('#text_area').val(data)
    });
}

Looking at your get_message function you should either change it to return just the message text instead of an array or else you'll need to json_encode the results and change the jQuery .get call to .getJSON instead.

answered Jul 6, 2012 at 11:10

davidethell

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Community · Accepted Answer · 2017-05-23 10:09:23Z

To use post in your ajax call:

function updateText()
{
    $.ajax({
        url: '/controller/get_message',
        data: {message_id:$('#frm_precan').val()},//no need to json encode, jQ does this for you
        type: 'POST',
        dataType: 'json',//or omit, jQ does an intelligent guess
        success: function(response)
        {
            console.log(responese);
            //function will be called when the ajax call is completed
        }
    });
}

In your controller, the get_message member function could look like this:

public function get_message()
{
    $id = $this->input->post('message_id');//=== data key used to send request
    //do your query 
}

Here is a similar question BTW
And here, you can find all sorts of things you can specify with the jQuery.ajax method ($.ajax is the same thing, $ and jQuery are synonyms)

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