6）靜態方法和prototype（難）
例 3.6.1
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8"/>
</head>
<script>
/*note that 馬克-to-win： static variable's value has nothing to do with instance's variable's value.instance 名稱 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就為undefined.This is different from Java，但在實體方法中（比如d1.info）可以訪問Student.number，這是和java中一樣的，或者說function外或任何地方都可以訪問Student.number，反過來，d1.age也可以在靜態方法中訪問，就像在function外一樣，任何地方都能訪問d1.age，String.prototype.abcd，這是給所有的實體加屬性而不是靜態屬性，*/
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屬性為means window.age" + this.age + "<br>");
document.writeln("d1的age屬性為" + d1.age + "<br>");
document.writeln("d1的number屬性為" + d1.number + "<br>");
document.writeln("通過Student訪問靜態number屬性為" + Student.number + "<br>");
document.writeln("d1的lb屬性為" + d1.lb + "<br><hr>");
d1.qixy = "abc";/*以隨意為實體加屬性或方法*/
document.writeln("可以隨意為實體加屬性或方法see following，d1的qixy屬性為" + d1.qixy + "<br><hr>");
document.writeln("是否有靜態變數qixy" + Student.qixy + "<br><hr>");
d1.info = function()/*此方法僅為d1物件所用*/
{
document.writeln("物件的qixy屬性:" + this.qixy);
document.writeln("物件的age屬性:" + this.age);
/*下列話是合法的， 因為不是this.number， 而是Student.number*/
document.writeln("static method is " + Student.number);
};
Student.prototype.infop = function()/*此方法可以為所有Student物件所用*/
{
document.writeln("物件的qixy屬性p:" + this.qixy);
document.writeln("物件的age屬性p:" + this.age);
文章轉載自：https://blog.csdn.net/qq_44594249/article/details/100053745
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標籤：JavaScript
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