Jquery .change() function not working with dynamic

问题:

I have a select field that is dynamically populated with an ajax call that simply returns all the HTML select options. Here is the part of the PHP that just echo's the select tags and dynamically fills out each option/value.

echo "<select name='player1' class='affector'>";
echo "<option value='' selected>--".sizeof($start)." PLAYERS LOADED--</option>";

foreach ($start as $value) {
    echo "<option value='".$value."'>".$value."</option>";
 }  
  echo "</select>";
}  

After this list is populated, I'm trying to call a change event, so that whenever the default option is changed in the SELECT list or in a text field with the same class, it disables a radio button set in another part of the form. (You can see the initial question I asked to get this part of the functionality working here)

$('.affector').change(function(){
       $(this).parents('tr').find('input:radio').attr('disabled', false);
});

For some reason, even though I give the select field the proper class name (affector), when I select different options in the field, the other parts of the form do not disable. The static text field with the same class works fine. I'm stumped.

Any ideas?

回答1:

Just commented on your last question...Here's what I said:

Use jQuery bind

function addSelectChange() {
   $('select').bind('change', function() {
       // yada yada
   });
} 

Call addSelectChange in your ajax success function. It should do the trick. Take a look at jQuery live event too (for when you want to set events for all current and future DOM elements in a later project or something). Unfortunately the change event and a few others aren't yet supported with live. Bind is the next best thing

回答2:

_{A more up to date answer..}

Since the elements are dynamically populated, you are looking for event delegation.

Don't use .live()/.bind()/.delegate(), though. You should use .on().

According to the jQuery API docs:

As of jQuery 1.7, the .on() method is the preferred method for attaching event handlers to a document. For earlier versions, the .bind() method is used for attaching an event handler directly to elements. Handlers are attached to the currently selected elements in the jQuery object, so those elements must exist at the point the call to .bind() occurs. For more flexible event binding, see the discussion of event delegation in .on().

Therefore you would use something like this:

$(document).on('change', 'select', function (e) {
    /* ... */
});

回答3:

An example using .live()

$('#my_form_id select[name^="my_select_name"]').live('change', (function () {
    console.log( $("option:selected", this).val());
    })
 );

回答4:

For items that are dynamically inserted into the DOM, their events must be bound with

$('.selector').bind('change',function() { doWork() });

This is because when you run $(function(){}); and bind events using $.click or $.change, etc., you are binding events to elements already existing in the DOM. Any manipulation you do after that does not get affected by whatever happens in the $(function(){}); call. $.bind tells your page to look for future elements in your selector as well as current ones.

回答5:

try .live: http://docs.jquery.com/Events/live

From docs: Binds a handler to an event (like click) for all current - and future - matched element. Can also bind custom events.

回答6:

I found as solution to make only

<select id="myselect"></select> 

in php/html file and then generate options for it by ajax:

$.post("options_generator.php", function (data) { $("#myselect").append(data); });

In options_generator.php echo options only:

echo "<option value='1'>1</option>";
echo "<option value='2'>2</option>";

回答7:

Use delegate() function instead. More about that here http://www.elijahmanor.com/differences-between-jquery-bind-vs-live-vs-delegate-vs-on/