'use strict';
/**
* ImagePreloader is a tool for multi-images preloading
*
* @example
* new ImagePreloader(['http://image1.jpg', 'http://image2.jpg'], function (oImage, this.aImages, this.nProcessed, this.nLoaded) {
* //use jQuery
* $('<img>').attr('src', oImage.src);
* });
*
* @author nhnst Liuming
* @version 20110623.4
* @constructor
* @param {String[]} images A collection of images url for preloading
* @param {Function} callback(oImage, this.aImages, this.nProcessed, this.nLoaded) A function to call once the every image request finishes
*/
function ImagePreloader(images, callback) {
this.callback = callback;
this.nLoaded = 0;
this.nProcessed = 0;
this.aImages = [];
this.nImages = images.length;
for (var i = 0, len = images.length ; i < len ; i += 1) {
this.preload(images[i], i);
}
}
/**
* Initialization
* @private
*/
ImagePreloader.prototype.preload = function (image, index) {
var oImage = new Image;
oImage.nIndex = index;
oImage.bLoaded = false;
oImage.oImagePreloader = this;
oImage.src = image + '?flush=' + (+new Date());
this.aImages.push(oImage);
// handle ie cache
if (oImage.width > 0) {
this.onload.call(oImage);
}
else {
oImage.onload = this.onload;
oImage.onerror = this.onerror;
oImage.onabort = this.onabort;
}
};
/**
* A inner function to be called when every image request finishes
* @private
*/
ImagePreloader.prototype.onComplete = function (oImage) {
this.nProcessed++;
this.callback(oImage, this.aImages, this.nProcessed, this.nLoaded);
};
/**
* A inner function to be called when image loads successful
* @private
*/
ImagePreloader.prototype.onload = function () {
this.bLoaded = true;
this.oImagePreloader.nLoaded++;
this.oImagePreloader.onComplete(this);
};
/**
* A inner function to be called when an error occurs loading the image
* @private
*/
ImagePreloader.prototype.onerror = function () {
this.bError = true;
this.oImagePreloader.onComplete(this);
};
/**
* A inner function to be called when image loading is aborted
* @private
*/
ImagePreloader.prototype.onabort = function () {
this.bAbort = true;
this.oImagePreloader.onComplete(this);
};
当我使用 jsdoc 生成 doc 文件时,会出现一些警告
>> WARNING: Trying to document ImagePreloader#onload without first documenting I
magePreloader.
>> WARNING: Trying to document ImagePreloader#onerror without first documenting
ImagePreloader.
>> WARNING: Trying to document ImagePreloader#onabort without first documenting
ImagePreloader.
3 warnings.
为什么?