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Populate a second DropDownList based on a selected value fron other DropDownList

Answer 1

A:

It sounds like you want AJAX. I'm not as up on this as I used to be, but the general procedure should go something like this:

When the user selects something in the first dropdown, it fires a javascript method. This method grabs that value, uses it to GET query a page via a XMLHttpRequest. The XMLHttpRequest has a callback, such that when the data comes back, you can populate the second dropdown with that data.

It's probably easiest (although somewhat odd) to have the PHP page that it calls just return the full HTML for the new dropdown. They you just have to do something like document.getElementById('secondDropdown').innerHTML = requestContent;.

zebediah49 2010-06-23 22:01:44

Answer 2

A:

It's easier if you use jQuery.

Here is an example.

In the main view you would have some like this:

<html>
<head>
<script type="text/javascript" src="jquery.js"></script>
</head>
<body>
<script>
    $('#dropdown1').change(function(e) {
        $('#dropdown2').load('some_controller/some_function/'+this.value);
    });
</script>

<select name="dropdown1" id="dropdown1">
    <option value="1">option 1</option>
    <option value="2">option 2</option>
</select>

<select name="dropdown2" id="dropdown2"></select>
</body>

You are saying in the script that whenever the dropdown change its value, you call (in Ajax) a controller function with the id in its arguments. Don't forget to include jQuery file.

In the controller, you would have this:

<?php
class some_controller extends Controller {

    function some_function($id) {
        $this->load->model('some_model');
        $data['options'] = $this->some_model->get_options($id);
        echo $this->load->view('view_dropdown2', $data, true);
    }
}
?>

So, when this function is called, you call your model function with the dropdown id, and you echo the view with the options. You have to put the 3rd argument true, so that the view is returned as a var and not rendered.

And in the view:

<?php foreach($options->result() as $option): ?>
    <option value="<?php echo $option->id; ?>"><?php echo $option->title; ?></option>
<?php endforeach; ?>

You are just creating the options tags because the select tag was already created in the main view.

dmb 2010-06-24 16:59:02

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Populate a second DropDownList based on a selected value fron other DropDownList

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