<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<script>
function fn(num1,num2,callback){
var num = num1 + num2;
callback(num)
}
fn(1,1,function(num){
console.log("回调函数返回的结果是:" + num)
})
</script>
</body>
</html>
在控制台中显示的结果.png
