求最大值
<script>
var arr=[2,4,2,55,44,60]
var max=Math.max.apply(null,arr)
//applay执行函数max用数组的方式去传递
console.log(max) //60
</script>
判断对象类型
<script>
//判断对象类型比使用typeof更准确
function getType(arg){
var type=Object.prototype.toString.call(arg);
return type.slice(8,-1)
}
console.log(getType([])) //Array
console.log(getType(/a/g)) //RegExp
console.log(getType(123)) //Number
console.log(getType("")) //String
</script>