<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script>
var array1=new Array(1,2,3,15);
var array2=new Array(10,20,30);
Array.prototype.sum=function ()
//array1.sum=function () //相当于行间样式
{
var result=0;
for(var i=0;i<this.length;i++) //this相当于Arry.prototype
{
result+=this[i];
}
return result;
};
alert(array1.sum());
alert(array2.sum());
</script>
</head>
<body>
</body>
</html>