javascript闭包的实现方式
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闭包说白了就是封装的意思..为了隐藏方法内部的实现细节..
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下面一段代码说明闭包的使用:
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<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>闭包的实现方式</title><script type="text/javascript">var commVar = 100;//闭包的实现方式一;//Ecmscript中所谓的闭包,函数能使用函数外定义的变量并且不需要传递参数;function showMessage(){alert(commVar);}showMessage();//闭包的实现方式二;//函数addNum()包括函数doAdd()闭包,内部函数是一个闭包,因为它将获取外部的参数num1和num2以及全局变量的值.function addNum(num1,num2){function doNum(){return commVar+num1+num2;}return doNum();}alert(addNum(10,10));//闭包实现方式三;function countNumFunction(num1){return function(num2){return num1 + num2;}}//引用闭包函数;var res = countNumFunction(10);alert(res(15));var sayHello = "hello ";//闭包实现方式四;(function(num1){var commName = "world";(function(){alert(sayHello+commName+":"+num1);})();})("500");//闭包实现方式五;function setDivStyle(message,time){setTimeout(function(){var divObj = document.createElement("div");var textObj = document.createTextNode(message);//把textObj对象追加到divObj中;divObj.appendChild(textObj);divObj.style.border="1px solid red";divObj.style.background = "green";document.body.appendChild(divObj);},time);}setDivStyle("javascript 实例!!",3000)setTimeout(function(){var pobj = document.getElementById("pid");pobj.style.display = "none";},3000);</script></head><body><p id="pid">Hello World!!!</p></body></html>?