如下面代码，想要它按照调用执行顺序来输出1,2
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<script>
var adopt=false
function a1(){
setTimeout(function(){
console.log(1)
},1000)
}
function a2(){
console.log(2)
}
function a3(){
a1()
a2()
}
a3()
</script>
</body>
</html>
但结果输出是2,1有时是1,2
很显然方法异步执行了，要改成异步可以用一个状态量来限制
<!DOCTYPE html><html lang="en"><head> ?<meta charset="UTF-8"> ?<meta name="viewport" content="width=device-width, initial-scale=1.0"> ?<meta http-equiv="X-UA-Compatible" content="ie=edge"> ?<title>Document</title></head><body> ?<script> ???var adopt = false ???function a1() { ?????console.log(1) ?????adopt = true ?????return adopt ???} ???function a2() { ?????console.log(2) ???} ???function a3() { ?????a1() ?????if (!adopt) { ???????return ?????} ?????a2() ???} ???a3() ?</script></body></html>这样就是每次输出都是1,2
这是我的片面测试，我对这个方法也不是十分确信，如果有发现错误或bug欢迎留言指正，谢谢！
js方法异步改同步解决
原文地址：https://www.cnblogs.com/yck123/p/10457372.html