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/**
* ¸¸ÀàPolygon:¶à±ßÐÎ
*
*/
function Polygon() {}
Polygon.prototype.sides = 0;
Polygon.prototype.setSides = function(s) {this.sides=s;}
/**
* ×ÓÀàTriangle:Èý½ÇÐÎ
*/
function Triangle() {}
Triangle.prototype = new Polygon();//¹Ø¼üÒ»¾ä
Triangle.prototype.getArea = function(){}
//new¸ö¶ÔÏó
var tri = new Triangle();
console.log(tri.sides);//¼Ì³ÐµÄÊôÐÔ
console.log(tri.setSides);//¼Ì³ÐµÄ·½·¨
console.log(tri.getArea);//×ÔÓз½·¨
//instanceof²âÊÔ
console.log(tri instanceof Triangle);//true£¬±íÃ÷¸Ã¶ÔÏóÊÇÈý½ÇÐÎ
console.log(tri instanceof Polygon);//true£¬±íÃ÷Èý½ÇÐÎÒ²ÊǶà±ßÐÎ

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JavaScript:history.go() µÄÃîÓÃ(ת)

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[·­Òë]High Performance JavaScript(006)

Identifier Resolution Performance  ±êʶ·ûʶ±ðÐÔÄÜ
    Identifier resolution isn't free, as in fact no computer operation really is without some sort of performance overhead. The deeper into the execution context's scope chain an identifier exists, the slower it is to access for ......

[·­Òë]High Performance JavaScript(009)

µÚÈýÕ  DOM Scripting  DOM±à³Ì
    DOM scripting is expensive, and it's a common performance bottleneck in rich web applications. This chapter discusses the areas of DOM scripting that can have a negative effect on an application's responsiveness and gives recommendations o ......
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