Is it possible to listen to a “style change” event

Question

Is it possible to create an event listener in jQuery that can be bound to any style changes? For example, if I want to "do" something when an element changes dimensions, or any other changes in the style attribute I could do:

$('div').bind('style', function() {
    console.log($(this).css('height'));
});

$('div').height(100); // yields '100'

It would be really useful.

Any ideas?

UPDATE

Sorry for answering this myself, but I wrote a neat solution that might fit someone else:

(function() {
    var ev = new $.Event('style'),
        orig = $.fn.css;
    $.fn.css = function() {
        $(this).trigger(ev);
        return orig.apply(this, arguments);
    }
})();

This will temporary override the internal prototype.css method and the redefine it with a trigger at the end. So it works like this:

$('p').bind('style', function(e) {
    console.log( $(this).attr('style') );
});

$('p').width(100);
$('p').css('color','red');

Answer 1

you can try Jquery plugin , it trigger events when css is change and its easy to use

http://meetselva.github.io/#gist-section-attrchangeExtension

 $([selector]).attrchange({
  trackValues: true, 
  callback: function (e) {
    //console.log( '<p>Attribute <b>' + e.attributeName +'</b> changed from <b>' + e.oldValue +'</b> to <b>' + e.newValue +'</b></p>');
    //event.attributeName - Attribute Name
    //event.oldValue - Prev Value
    //event.newValue - New Value
  }
});

Answer 2

There is no inbuilt support for the style change event in jQuery or in java script. But jQuery supports to create custom event and listen to it but every time there is a change, you should have a way to trigger it on yourself. So it will not be a complete solution.

Answer 3

The declaration of your event object has to be inside your new css function. Otherwise the event can only be fired once.

(function() {
    orig = $.fn.css;
    $.fn.css = function() {
        var ev = new $.Event('style');
        orig.apply(this, arguments);
        $(this).trigger(ev);
    }
})();

Answer 4

I had the same problem, so I wrote this. It works rather well. Looks great if you mix it with some CSS transitions.

function toggle_visibility(id) {
   var e = document.getElementById("mjwelcome");
   if(e.style.height == '')
      e.style.height = '0px';
   else
      e.style.height = '';
}

Answer 5

Interesting question. The problem is that height() does not accept a callback, so you wouldn't be able to fire up a callback. Use either animate() or css() to set the height and then trigger the custom event in the callback. Here is an example using animate() , tested and works (demo), as a proof of concept :

$('#test').bind('style', function() {
    alert($(this).css('height'));
});

$('#test').animate({height: 100},function(){
$(this).trigger('style');
}); 

Answer 6

Since jQuery is open-source, I would guess that you could tweak the css function to call a function of your choice every time it is invoked (passing the jQuery object). Of course, you'll want to scour the jQuery code to make sure there is nothing else it uses internally to set CSS properties. Ideally, you'd want to write a separate plugin for jQuery so that it does not interfere with the jQuery library itself, but you'll have to decide whether or not that is feasible for your project.