Asked  7 Months ago    Answers:  5   Viewed   14 times

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');

 Answers

63

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.

Tuesday, June 1, 2021
 
daiscog
answered 7 Months ago
43

Unfortunately, assignment to innerHTML causes the destruction of all child elements, even if you're trying to append. If you want to preserve child nodes (and their event handlers), you'll need to use DOM functions:

function start() {
    var myspan = document.getElementById("myspan");
    myspan.onclick = function() { alert ("hi"); };

    var mydiv = document.getElementById("mydiv");
    mydiv.appendChild(document.createTextNode("bar"));
}

Edit: Bob's solution, from the comments. Post your answer, Bob! Get credit for it. :-)

function start() {
    var myspan = document.getElementById("myspan");
    myspan.onclick = function() { alert ("hi"); };

    var mydiv = document.getElementById("mydiv");
    var newcontent = document.createElement('div');
    newcontent.innerHTML = "bar";

    while (newcontent.firstChild) {
        mydiv.appendChild(newcontent.firstChild);
    }
}
Tuesday, June 1, 2021
 
FyodorX
answered 7 Months ago
28

Thanks for the comments guys. I've gone with the following:

var EntriesRegistry = (function(){

    var instance = null;

    function __constructor() {

        var
            self = this,
            observations = {};

        this.set = function(n,v)
        {
            self[n] = v;

            if( observations[n] )
                for( var i=0; i < observations[n].length; i++ )
                    observations[n][i].apply(null, [v, n]);

        }

        this.get = function(n)
        {
            return self[n];
        }

        this.observe = function(n,f)
        {

            if(observations[n] == undefined)
                observations[n] = [];

            observations[n].push(f);
        }

    }

    return new function(){
        this.getInstance = function(){
            if (instance == null)
            {
                instance = new __constructor();
                instance.constructor = null;
            }
            return instance;
        }
    }
})();

var entries = EntriesRegistry.getInstance();

var test = function(v){ alert(v); };

entries.set('bob', 'meh');

entries.get('bob');

entries.observe('seth', test);

entries.set('seth', 'dave');

Taking on-board your comments, I'll be using event delegation on the form objects to update the registry and trigger the registered observing methods.

This is working well for me so far... can you guys see any problems with this?

Wednesday, June 30, 2021
 
Ula
answered 5 Months ago
Ula
61

You may also checkout the UI.Layout jQuery plugin. Here's a demo.

Sunday, August 8, 2021
 
Scott Chantry
answered 4 Months ago
91

As I tried out and read through the link given by @konrad, I found that its a bug in Jquery UI - even in the latest version of it. The problem got solved as soon as I started using Jquery UI 1.9.2 version

here is the updated fiddle: http://jsfiddle.net/deveshz/YvmFf/2/

with same code:

var zindex = 10; 
$(".item").draggable({
    containment: "body",
    scroll: true,
    revert: function (event, ui) {
        $(this).css("border", "none");
        return !event;
   },
    start: function (event, ui) {
        $(this).css("z-index", zindex++);
        $(this).css("border", "2px solid #333");
    }
});

 $(".stack_items").droppable({
    hoverClass: "over",
    drop: function (event, ui) {
        $("<li class='item'></li>").html(ui.draggable.html()).appendTo(this);
        $(ui.draggable).remove();
    }
});

It uses Jquery version 1.9.2 from http://cdnjs.cloudflare.com/ajax/libs/jqueryui/1.9.2/jquery-ui.min.js

Wednesday, August 25, 2021
 
StampyCode
answered 3 Months ago
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