4）Function用法
例 3.4.1
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8"/>
</head>
<script>
/*When the Global object is created, it always has at least the following properties:
Object object
Function object
Array object
String object
Boolean object
Number object
Date object
Math object
Value properties
*/
/*Function的好处是， 函数体可以是运行时的一个传入的动态字符串，for the Function class, the last parameter is
function body, while the parameters before the last one are input arguments., 'x' can be changed to "x" */
var a='return x + y;';
var f = new Function('x', 'y',a );// 等价于var f = function(x, y){return x + y;}
document.write(f(1, 1));
</script>
文章转载自：https://blog.csdn.net/qq_44594249/article/details/100015900