javascript当中静态方法和prototype用法

马克java社区

修改于 2019-10-09 17:44:49

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修改于 2019-10-09 17:44:49

文章被收录于专栏：java大数据

6）静态方法和prototype（难） 例 3.6.1 <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"/> </head> <script> /*note that 马克-to-win： static variable's value has nothing to do with instance's variable's value.instance 名称 can not 直接access static member like in java. This is different from Java，比如下面例子中，Student.number=2,但是d1.number就为undefined.This is different from Java，但在实例方法中（比如d1.info）可以访问Student.number。这是和java中一样的。或者说function外或任何地方都可以访问Student.number。反过来，d1.age也可以在静态方法中访问，就像在function外一样，任何地方都能访问d1.age。String.prototype.abcd，这是给所有的实例加属性而不是静态属性。*/ function Student(number, agev) { this.age = agev; /*static variable's value can not be accessed by instance */ Student.number = number; /*lb is local variable, but not a member variable because it is not modified by this. from outside it can not be accessed. refer to noblockScope.html */ var lb = 0; } var d1 = new Student(1, 3); document.writeln("this的age属性为means window.age" + this.age + " "); document.writeln("d1的age属性为" + d1.age + " "); document.writeln("d1的number属性为" + d1.number + " "); document.writeln("通过Student访问静态number属性为" + Student.number + " "); document.writeln("d1的lb属性为" + d1.lb + " <hr>"); d1.qixy = "abc";/*以随意为实例加属性或方法*/ document.writeln("可以随意为实例加属性或方法see following，d1的qixy属性为" + d1.qixy + " <hr>"); document.writeln("是否有静态变量qixy" + Student.qixy + " <hr>"); d1.info = function()/*此方法仅为d1对象所用*/ { document.writeln("对象的qixy属性:" + this.qixy); document.writeln("对象的age属性:" + this.age); /*下列话是合法的，因为不是this.number，而是Student.number*/ document.writeln("static method is " + Student.number); }; Student.prototype.infop = function()/*此方法可以为所有Student对象所用*/ { document.writeln("对象的qixy属性p:" + this.qixy); document.writeln("对象的age属性p:" + this.age);

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