jQuery Ajax wait until all images are loaded

问题

I\'m trying to perform an Ajax call with jQuery which is working well. I use the success event to display the data. It seems however that success gets triggered as soon as the external HTML file gets loaded. If there are large images they keep loading after they\'re shown. Is there a way to display the content after everything is fully loaded? Here is the code:

$(\'#divajax\').html(\'<br><div style=\"text-align: center;\"><img src=\"res/ajax-loader.gif\"></div>\');
$.ajax({
    cache: false,
    url: \'ajax/content.php\',
    success: function(data) {
          $(\'#divajax\').html(data);
    }
});

回答1:

The plugin that @alex wrote didn't work for me for some reason... I couldn't figure out why. But his code did inspire me to come up with a more lightweight solution that is working for me. It uses jquery promises. Please note that unlike @alex 's plugin, this doesn't attempt to account for background images on elements, only img elements.

// Fn to allow an event to fire after all images are loaded
$.fn.imagesLoaded = function () {

    // get all the images (excluding those with no src attribute)
    var $imgs = this.find('img[src!=""]');
    // if there's no images, just return an already resolved promise
    if (!$imgs.length) {return $.Deferred().resolve().promise();}

    // for each image, add a deferred object to the array which resolves when the image is loaded (or if loading fails)
    var dfds = [];  
    $imgs.each(function(){

        var dfd = $.Deferred();
        dfds.push(dfd);
        var img = new Image();
        img.onload = function(){dfd.resolve();}
        img.onerror = function(){dfd.resolve();}
        img.src = this.src;

    });

    // return a master promise object which will resolve when all the deferred objects have resolved
    // IE - when all the images are loaded
    return $.when.apply($,dfds);

}

Then you can use it something like this:

$.ajax({
    cache: false,
    url: 'ajax/content.php',
    success: function(data) {
        $('#divajax').html(data).imagesLoaded().then(function(){
            // do stuff after images are loaded here
        });
    }
});

Hopefully that's helpful for someone.

Note that using the above code, if one of the images errors (eg because the URL was wrong), the promise is resolved anyway and the error is ignored. This might be what you want, but, depending on your situation, you might instead want to abort whatever you are doing if an image fails to load. In which case you could replace the onerror line as follows:

img.onerror = function(){dfd.reject();}

And catch the error like this:

$('#divajax').html(data).imagesLoaded().done(function(){
    // do stuff after all images are loaded successfully here
}).fail(function(){
    // do stuff if any one of the images fails to load
});

回答2:

You could use my jQuery plugin, waitForImages...

$.ajax({
    cache: false,
    url: 'ajax/content.php',
    success: function(data) {

         $('#divajax').html(data).hide().waitForImages(function() {
             $(this).show();
         });

    }
});

This will load the stuff into your element, hide it, and then reshow it once descendent img elements have loaded.

回答3:

You can bind something to the load events to know when they're done:

$('<img>').bind('load', function() {
    $(this).appendTo('body');
});

Or you could use this plugin.

回答4:

this triggers on every img load separately:

$('img').on('load', function() {
      // do something
});

i used:

var loaded = 0;
$('img').on('load', function() {
   loaded++;
   if(loaded == $('img').length){
      // do something
   }
});

回答5:

You can use imagesloaded plugin that is work with JavaScript and jQuery, try to use inside ajax success callback function on loaded content, and hide all content while imagesloaded callback function not trigger, see below sample code

$.ajax({
    cache: false,
    url: 'ajax/content.php',
    success: function(data) {
        var $divajax = $('#divajax').html(data).hide();
        $divajax.imagesLoaded(function() {
             $divajax.show();
         });

    }
});

回答6:

Look into using jquery's .load()

Which has a description of :

The load event is sent to an element when it and all sub-elements have been completely loaded. This event can be sent to any element associated with a URL: images, scripts, frames, iframes, and the window object.

回答7:

$('#divajax').html('<br><div style="text-align: center;"><img src="res/ajax-loader.gif"></div>').load(function() {
$.ajax({
    cache: false,
    url: 'ajax/content.php',
    success: function(data) {
          $('#divajax').html(data);
    }
});
});

回答8:

Try this code. It works fine.

$.ajax({
    url: "../api/listings",
    type: 'GET',
    success: function (html) {
        $('#container').append(html);
        $('#container img').on('load', function(){console.log('images loaded')});
    };
});

回答9:

I've got a small bug when no images are found by the plugin from Daniel's solution.

Just in case some else get the same issue:

Change:

// if there's no images, just return an already resolved promise
if (!$imgs.length) {return $.Deferred.resolve().promise();}

To :

// if there's no images, just return an already resolved promise
    if (!$imgs.length) {
        var dfd = $.Deferred();
        return dfd.resolve().promise();
    }

回答10:

i think the best is using this

$(window).ready(function(){ //load your ajax})

来源：https://stackoverflow.com/questions/4774746/jquery-ajax-wait-until-all-images-are-loaded