<html>
<head>
</head>
<body>
</body>
<script>
function s1(){
var x=parseInt(prompt("请输入数字",1));
return x;}
function s2(){
var y=parseInt(prompt("请输入数字",1));
return y;}
function f(){
var op=parseString(prompt("请输入算法","add"));
return op;}
alert(option(f(),s1(),s2()));
function option(op,x,y){
var result=op(x,y)
return(result);
}
function add(x,y){return x+y;}
function sub(x,y){return x-y;}
function mul(x,y){return x*y;}
function div(x,y){return x/y;}
</script>
</html>
原文：http://www.cnblogs.com/Cheng1367959758/p/4853482.html