js中自定義方法實作停留幾秒sleep

js中不存在自帶的sleep方法，要想休眠要自己定義個方法

function sleep(numberMillis) { 
var now = new Date(); 
var exitTime = now.getTime() + numberMillis; 
while (true) { 
now = new Date(); 
if (now.getTime() > exitTime) 
return; 
} 
}
           

蹩腳的解決方案:

最簡單也最糟糕的方法就是寫一個循環，代碼可能如下：

function sleep(numberMillis) {
    var now = new Date();
    var exitTime = now.getTime() + numberMillis;
    while (true) {
        now = new Date();
        if (now.getTime() > exitTime)
            return;
    }
}