function Point() {
this.x = 20;
this.getX = function() { return this.x; }
}
var a = new Point();
var f = a.getX;
alert(f());
/*
ES6
class Point {
constructor() {
this.x = 20;
}
getX() {
return this.x;
}
}
var a = new Point();
var f = a.getX;
alert(f());
*/
<p><b>Question:</b></p>
What will this code alert? Why?
<p><b>题目:</b></p>
按「Run」会出现什麽提示呢?为什麽呢?