而真正的循环冻结了broswers javascript [英] while true loop freezes up broswers javascript

问题描述

所以我试图让图像改变并使它们成为一个循环，我想出了这个脚本，而我遇到的问题是，当它改为第二张图片时，javascript会冻结在我身上，我知道它虽然（真）部分，但我不知道如何解决它，请帮助。
谢谢你

so im trying to make the images change and make them into a loop and i came up with this script, and the problem i am having is that, when it change to the second picture the javascript would freeze up on me, I know it the while(true) part but i dont know how to fix it, please help.
thanks you

var images = new Array();
images[0] = "image1.jpg";
images[1] = "image2.jpg";
images[2] = "image3.jpg";
setTimeout("changeImage()", 3000);
var x=0;

function changeImage()
{
    while(true){
        document.getElementById("img").src=images[x]
        x++;
    }

    if (x=2){
        x=0;
    }
}

推荐答案

啊，我明白你要做什么。

Ah, I see what you're trying to do.

而（true）将永远循环同步。你想要的是每3秒不断更换图像（异步）。

while (true) is going to loop forever synchronously. What you want is to continually change images every 3 seconds (asynchronously).

试试这个：

var timeoutId = null;

function changeImage() {
  document.getElementById("img").src = images[x];
  x = (x + 1) % images.length;
  timeoutId = setTimeout(changeImage, 3000);
}

这样， changeImage 永远不会循环;但是每次调用它都会在3秒钟内安排另一次调用 changeImage 。此异步过程将无限期地继续（您尝试使用而（true）），直到用户离开页面或您选择调用 clearTimeout （timeoutId）。

This way, changeImage will not loop forever; but every time it's called it will schedule another call to changeImage in 3 more seconds. This asynchronous process will continue indefinitely (what you were trying to do with while (true)) until the user leaves the page or you choose to call clearTimeout(timeoutId).

请注意，您还可以摆脱全局变量 x 将它作为 changeImage 的参数，如下所示：

Note that you could also get rid of the global variable x by making it a parameter to changeImage, like this:

function changeImage(x) {
  document.getElementById("img").src = images[x];
  timeoutId = setTimeout(function() {
    changeImage((x + 1) % images.length);
  }, 3000);
}

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