In the short form, they are necessary for the JSON (JavaScript Object
Notation) syntax. You're best bet is to read up on JSON online at
json.org. Essentially, by adding the curly braces, you told the browser
to create a javascript object with a property named "chosen_option" with
a value of $F("choose_first"). Then, the prototype.js Ajax object can
us that object to accurately send the information to your server.
Since you're using PHP, there are some classes out there which can
create JSON objects from associative PHP arrays. Then, you can use the
x-json header to send a JSON object back to your client which is a
little lighter in weight than XML for complex data representation.
-- Dash --
lukemack wrote:
> disco! you the man. thanks loads for your help. can you explain what
> the curly braces do?
>
> On 5 Mar, 16:12, David Dashifen Kees <[EMAIL PROTECTED]> wrote:
>
>> My bad. Put curly braces ({ and }) around the parameters like this:
>>
>> { chosen_option: $F("choose_first") } and you should be good to go.
>>
>> Or, if you prefer, you can use the following syntax because it looks
>> more like a url:
>>
>> parameters: "chosen_option="+$F("choose_first")
>>
>> It's up to you.
>>
>> -- Dash --
>>
>>
>>> I got a bit further. I understand the $F bit now. However, I'm only
>>> getting the following in my $_GET array in PHP:
>>>
>>> Array
>>> (
>>> [url] => tests/ships
>>> [13] =>
>>> )
>>>
>>> so the array's key has become the value I want. how can i get this in
>>> the same form as the url value?
>>>
>>> On 5 Mar, 15:38, "lukemack" <[EMAIL PROTECTED]> wrote:
>>>
>>>> thanks very much for your reply.
>>>>
>>>> what is $F? I should point out that I am not using this within Rails.
>>>> I was directed here by someone at the javascript group.
>>>>
>>>> your code gives me the following error:
>>>>
>>>> Error: missing } after property list
>>>> Source File: xxxxxxx
>>>> Line: 33, Column: 32
>>>> Source Code:
>>>> "get", parameters: chosen_option: $F("element_id") });
>>>>
>>>> thanks,
>>>>
>>>> lukemack.
>>>>
>>>> On 5 Mar, 14:48, David Dashifen Kees <[EMAIL PROTECTED]> wrote:
>>>>
>>>>> You should be able to use an onChange event on the first select box to
>>>>> create an Ajax.Updater object with a parameter equaling the value of the
>>>>> select box. Essentially:
>>>>>
>>>>> <select id="choose_first" onChange="get_second_list()">
>>>>> <option>....</option>
>>>>> </select>
>>>>>
>>>>> <div id="second_list"></div>
>>>>>
>>>>> <script type="text/javascript">
>>>>> function get_second_list() {
>>>>> new Ajax.Updater("second_list", "get_second_list.php", { method:
>>>>> "get", parameters: chosen_option: $F("choose_first") });
>>>>> }
>>>>> </script>
>>>>>
>>>>> Your preference for unobtrusive Event.observe() calls versus inline
>>>>> event handlers may alter the code and there may be better ways to do
>>>>> this rather than using the empty div, but this should illustrate the
>>>>> basics. The get_second_list.php page would have to get the value out of
>>>>> the $_GET array, process it, and construct the neccessary select box
>>>>> which would be placed in the "second_list" div.
>>>>>
>>>>> Write back if you're still confused.
>>>>>
>>>>> -- Dash --
>>>>>
>>>>> lukemack wrote:
>>>>>
>>>>>> hi,
>>>>>>
>>>>>> i am trying to make the contents of one drop-down box dependent on the
>>>>>> contents of another using AJAX (prototype.js) and PHP
>>>>>>
>>>>>> I have it working so that a new dropdown appears when i select a value
>>>>>> in the first dropdown:
>>>>>>
>>>>>> <?php echo $html->selectTag('Review/cruiseline', $cruise_lines, null,
>>>>>> array('onchange'=>'new Ajax.Updater(\'test\', \'ships?variable=12\',
>>>>>> { method: \'get\' }, {asynchronous:true, evalScripts:true});'), null,
>>>>>> true, false);?>
>>>>>>
>>>>>> In my php script (which is located at URL 'ships'), I am just getting
>>>>>> the value of 'variable' from the $_GET super global but I obviously
>>>>>> want that value to be dynamic and equal to the value selected in the
>>>>>> dropdown.
>>>>>>
>>>>>> So the missing piece is passing the selected dropdown value from
>>>>>> HTML / Javascript to PHP. Anyone know how to do that?
>>>>>>
>>>>>> thanks,
>>>>>>
>>>>>> lukemack.
>>>>>>
>
>
> >
>
>
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