手写Promise
2020-11-09 本文已影响0人
鱼香肉丝没有渔
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<button id="btn">摇数字1-8</button>
<div></div>
<script>
var b = document.getElementById("btn");
var div = document.querySelector('div');
b.onclick = function (){
var p = new Promise(function(resolve,reject){
setTimeout(()=>{
let n = parseInt(Math.random()* 7 + 1,10);
resolve(n)
},1000);
});
p.then((x) =>{
div.innerText ='数字是' + x
},(err)=>{
console.log('失败'+ err)
});
}
</script>
</body>
</html>
<script>
function 摇(){
return new Promise(function(resolve,reject){
setTimeout(()=>{
let n = parseInt(Math.random()* 7 + 1,10);
resolve(n)
},1000);
});
}
摇().then(
x =>{
console.log('数字是' + x);
},()=>{
console.log('失败')
});
</script>
Promise.all
Promise.all([
$.ajax({url:'data/arr.txt',dataType:'json'}),
$.ajax({url:'data/json.txt',dataType:'json'}),
]).then((results)=>{
let [arr,json] = results;
alert('成功')
}),()=>alert('失败')
