1, understand prototype
prototype property in JavaScript in the end What do you mean?
2, to the official target (class) increased Array method is the use of prototype
<!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>
<style type="text/css">
</style>
</head>
<body>
<input type="button" value="测试" onclick="testf()" />
</body>
</html>
<script type="text/javascript">
//这是个面试题：如何给官方的类增加方法。
Array.prototype.max = function () {
let m = this[0];//this是数组对象，调用max函数的数组对象
for(let i=1;i<this.length;i++){
if(this[i]>m){
m = this[i];
}
}
return m;
}
let arr = new Array(12,222,13,50,18);
let m = arr.max();
console.log(m);
</script>
