JavaScript控制图片加载完成后调用回调函数的方法_javascript技巧

function when_images_loaded($img_container, callback) {
/* do callback when images in $img_container (jQuery object) are loaded. Only works when ALL images in $img_container are newly inserted images and this function is called immediately after images are inserted into the target. */
var _imgs = $img_container.find('img'),
img_length = _imgs.length,
img_load_cntr = 0;
if (img_length) {//if the $img_container contains new images.
_imgs.on('load', function() {//then we avoid the callback until images are loaded
img_load_cntr++;
if (img_load_cntr == img_length) {
callback();
}
});
}
else { //otherwise just do the main callback action if there's no images in $img_container.
callback();
}
}