javascript 超时/睡眠使用 setTimeout()
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javascript timeout/sleep using setTimeout()
提问by Jay
How can I set a 2 second timeout to wait for page controls to be populated? I want to use javascript I have tried the following but to no avail:
如何设置 2 秒超时以等待填充页面控件？我想使用 javascript 我尝试了以下但无济于事：
setTimeout(function(){},2000);
setTimeout(2000);
Anyone able to provide a pointer?
任何人都可以提供一个指针？
回答by Coop
setTimeout(function(){
//put your code in here to be delayed by 2 seconds
},2000);
The code you want to delay needs to sit inside the setTimeout function.
您想要延迟的代码需要位于 setTimeout 函数内。
回答by Suresh Atta
回答by Craig Hicks
NOTE: Part of this answer is identical to another more popular answer, but this answer also includes output to make clear that the constructed sleep()permits independent loops in the same thread to run interleaved.
注意：此答案的一部分与另一个更受欢迎的答案相同，但此答案还包括输出，以明确构造sleep()允许同一线程中的独立循环交错运行。
ECMAScript Latest Draft (ECMA-262). As of 2019, supported in most broswers, but not IE.
ECMAScript 最新草案 (ECMA-262)。截至 2019 年，大多数浏览器都支持，但不支持 IE。
function sleep(n) { return new Promise(resolve=>setTimeout(resolve,n)); }
async function LoopA() {
for (let i=0;i<10;i++) {
console.log("LoopA i=",i,
",sec=",performance.now().toFixed(0)/1000);
await sleep(1000);
}
}
async function LoopB() {
for (let i=0;i<10;i++) {
console.log("LoopB i=",i,
",sec=",performance.now().toFixed(0)/1000);
await sleep(1000);
}
}
LoopA();
LoopB();
has sample output:
有样本输出：
LoopA i= 0 ,sec= 1648.665
LoopB i= 0 ,sec= 1648.665
LoopA i= 1 ,sec= 1649.666
LoopB i= 1 ,sec= 1649.667
LoopA i= 2 ,sec= 1650.667
LoopB i= 2 ,sec= 1650.669
LoopA i= 3 ,sec= 1651.669
LoopB i= 3 ,sec= 1651.67
LoopA i= 4 ,sec= 1652.67
LoopB i= 4 ,sec= 1652.671
LoopA i= 5 ,sec= 1653.671
LoopB i= 5 ,sec= 1653.672
LoopA i= 6 ,sec= 1654.672
LoopB i= 6 ,sec= 1654.674
LoopA i= 7 ,sec= 1655.674
LoopB i= 7 ,sec= 1655.675
LoopA i= 8 ,sec= 1656.675
LoopB i= 8 ,sec= 1656.676
LoopA i= 9 ,sec= 1657.677
LoopB i= 9 ,sec= 1657.678
