添加的类不会触发其jQuery函数

Question

It's an audio player: the idea is that the play button turns into a pause button (and viceversa) when clicked.

Thing is that the .pause event doesn't trigger the following function:

$('.pause').click(function(){
    player.pause();

    $(this).addClass('play');
    $(this).removeClass('pause');
});

The css shows that the pause class is set, but the function doesn't work. Is there a way to make it work? (would be great to know why it didn't work)

jsFiddle

Answer 1

Use a delegated event binding to bind a handler that will be selector-aware without requiring rebinding on events.

For the purposes of your demo, the selector would be along the lines of:

$('.player_controls').on('click', '.pause', function () {...});

Delegate event bindings attach the listener to a parent element that checks to see if the event fired was fired on an element that matches the provided selector.

_{jQuery docs}

When a selector is provided, the event handler is referred to as delegated . The handler is not called when the event occurs directly on the bound element, but only for descendants (inner elements) that match the selector. jQuery bubbles the event from the event target up to the element where the handler is attached (ie, innermost to outermost element) and runs the handler for any elements along that path matching the selector.

Event handlers are bound only to the currently selected elements; they must exist on the page at the time your code makes the call to .on() . To ensure the elements are present and can be selected, perform event binding inside a document ready handler for elements that are in the HTML markup on the page. If new HTML is being injected into the page, select the elements and attach event handlers after the new HTML is placed into the page. Or, use delegated events to attach an event handler, as described next.

Delegated events have the advantage that they can process events from descendant elements that are added to the document at a later time. By picking an element that is guaranteed to be present at the time the delegated event handler is attached, you can use delegated events to avoid the need to frequently attach and remove event handlers. This element could be the container element of a view in a Model-View-Controller design, for example, or document if the event handler wants to monitor all bubbling events in the document. The document element is available in the head of the document before loading any other HTML, so it is safe to attach events there without waiting for the document to be ready.

Answer 2

You can use event delegation for this. The issue is that binding directly (without delegation) binds to whichever elements exist at the time click is called.

$(".player_controls").on("click", ".pause", function(){

    /* ... */

});

Answer 3

Instead of using $('.pause').click(function(){...}) you would need to start using the $.on method to start listening for objects which are still not in the DOM. eg

$(".pause").parent().on("click",".pause", function(event){
    player.pause();
    $(this).addClass('play');
    $(this).removeClass('pause');
});