Create a jQuery special event for content changed

问题:

I'm trying to create a jQuery special event that triggers when the content that is bound, changes. My method is checking the content with a setInterval and check if the content has changed from last time. If you have any better method of doing that, let me know. Another problem is that I can't seem to clear the interval. Anyway, what I need is the best way to check for content changes with the event.special.

(function(){

    var interval;

    jQuery.event.special.contentchange = {
        setup: function(data, namespaces) {
            var $this = $(this);
            var $originalContent = $this.text();
            interval = setInterval(function(){
                if($originalContent != $this.text()) {
                    console.log('content changed');
                    $originalContent = $this.text();
                    jQuery.event.special.contentchange.handler();
                }
            },500);
        },
        teardown: function(namespaces){
            clearInterval(interval);
        },
        handler: function(namespaces) {
            jQuery.event.handle.apply(this, arguments)
        }
    };

})();

And bind it like this:

$('#container').bind('contentchange', function() {
        console.log('contentchange triggered');
});

I get the console.log 'content changed', but not the console.log 'contentchange triggered'. So it's obvious that the callback is never triggered.

I just use Firebug to change the content and to trigger the event, to test it out.

Update
I don't think I made this clear enough, my code doesn't actually work. I'm looking for what I'm doing wrong.

Here is the finished code for anyone interested

(function(){

    var interval;

    jQuery.event.special.contentchange = {
        setup: function(){
            var self = this,
            $this = $(this),
            $originalContent = $this.text();
            interval = setInterval(function(){
                if($originalContent != $this.text()) {
                    $originalContent = $this.text();
                    jQuery.event.handle.call(self, {type:'contentchange'});
                }
            },100);
        },
        teardown: function(){
            clearInterval(interval);
        }
    };

})();

Thanks to Mushex for helping me out.

回答1:

also take a look to James similar script (declaring as jquery object method and not as event)

jQuery.fn.watch = function( id, fn ) {

    return this.each(function(){

        var self = this;

        var oldVal = self[id];
        $(self).data(
            'watch_timer',
            setInterval(function(){
                if (self[id] !== oldVal) {
                    fn.call(self, id, oldVal, self[id]);
                    oldVal = self[id];
                }
            }, 100)
        );

    });

    return self;
};

jQuery.fn.unwatch = function( id ) {

    return this.each(function(){
        clearInterval( $(this).data('watch_timer') );
    });

};

and creating special event

jQuery.fn.valuechange = function(fn) {
    return this.bind('valuechange', fn);
};

jQuery.event.special.valuechange = {

    setup: function() {

        jQuery(this).watch('value', function(){
            jQuery.event.handle.call(this, {type:'valuechange'});
        });

    },

    teardown: function() {
        jQuery(this).unwatch('value');
    }

};

Anyway, if you need it only as event, you script is nice :)

回答2:

I know this post/question is a little old, but these days I was behind a similar solution and I found this:

$('#selector').bind('DOMNodeInserted', function(e) {
    console.log(e.target);
});

Source: http://naspinski.net/post/Monitoring-a-DOM-Element-for-Modification-with-jQuery.aspx

Hope this help someone!

回答3:

The finished code in the original question worked for me, thank you! I would just like to note that I am using jquery 1.9.1 and $.event.handle seems to have been removed. I changed the following to get it to work.

jQuery.event.handle.call(self, {type:'contentchange'});

to

jQuery.event.dispatch.call(self, {type:'contentchange'});

回答4:

maybe you could try Mutation Observer

Here are the code:

mainArea = document.querySelector("#main_area");
MutationObserver = window.MutationObserver;
DocumentObserver = new MutationObserver(function() {
       //what you want to run
});

DocumentObserverConfig = {attributes: true, childList: true, characterData: true, subtree: true};

DocumentObserver.observe(mainArea, DocumentObserverConfig);