一、作为数据的函数

function square(x){return x*x}
//定义了一个新的函数对象，并把这个对象赋给了变量 square
var a=square(4);
var b=square;
var c=b(5);

//除了赋给变量外，还可以赋给对象的属性，这种情况下，我们称函数为方法
var o=new object;
o.square=function(x){return x*x}
y=o.square(16);

//函数也可以没有函数名
var a=new Array(3);
a[0]=function(x){returnp x*x}
a[1]=20;
a[2]=a[0]{a[1]};

//将函数作为数据的所有用法
function add(x,y){return x+y;}
function subtract(x,y){return x-y;}
function multiply(x,y){return x*y;}
function divide(x,y){return x/y}

function operate(operator,operand1,operand2)
{
	return operator(operand1,operand2);
}

var i=operate(add,operate(add,2,3),operate(multiply,4,5));

var operators={
	add: function(x,y){return x+y},
	subtract: function(x,y){return x-y},
	multiply: function(x,y){return x*y},
	divide: function(x,y){return x/y},
	pow: Math.pow
};

function operate2(op_name,operand1,operand2)
{
	if(typeof operators[op_name]=="function")
		return operators[op_name](operand1,operand2);
	else throw "unknown operator";
}

var j=operate2("add","hello",operates("add"," ","world"))
var k=operate2("pow",10,2)
二、作为方法的函数

//this 用来调用方法的对象成为关键字this的值
var calculator={
	operand1:1,
	operand2:1,
	compute:function()
	{
		this.result=this.operand1+this.operand2;
	}
};
calculator.compute();
print(calculator.result);