<!DOCTYPE html>charset="utf-8"W3Cschool教程(w3cschool.cn)id="demo"单击按钮来调用新的myMet()方法,并显示55一半数量值,使用新的构造函数myProp()。onclick="myFunction()"点我Number.prototype.myMet=function(){this.myProp=this.valueOf()/2;}function myFunction(){var d = new Number(55);d.myMet();var x=document.getElementById("demo");x.innerHTML=d.myProp;}