本文介绍了加载所有图像后如何发出警报?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着跟版网的小编来一起学习吧！
问题描述
我正在构建一个 JavaScript 游戏，我想在加载所有图像后发出警报.我试过这段代码，但它不起作用:
I'm building a JavaScript game and I want to alert after all images are loaded. I tried this code but it's not working:
function loadEveryThing() {
var imgNumber = 0;
img1 = new Image();
img1.src = "1.png"
img1.onload = function() {
imgNumber = imgNumber + 1;
}
img2 = new Image();
img2.src = "2.png"
img2.onload = function() {
imgNumber = imgNumber + 1;
}
img3 = new Image();
img3.src = "3.png"
img3.onload = function() {
imgNumber = imgNumber + 1;
}
if (imgNumber == 3) alert("done")
}
推荐答案
图片正在异步加载.您的检查器代码将在任何图像加载之前运行.我建议您对每个图像加载进行检查.比如:
The images are loading asynchronously. Your checker code will run before any of the images get loaded. I suggest you do the checks for each image load. Something like:
function loadImages(urls,callback){
//counter
var counter = 0;
//checking function
function check(){
counter++;
if(urls.length === counter) callback();
}
//for each image, attach the handler and load
for(var i = urls.length; i--;){
img = new Image();
img3.onload = check;
img.src= urls[i]
}
}
loadImages([/*array of urls*/],function(){
//this function fires when all images have loaded
});
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