第一种方法:
function Point(x, y) {
this.x = x;
this.y = y;
this.delta = function (delta) {
this.x += delta.x;
this.y += delta.y;
}
}
生成的每个对象都有一份delta()函数:
第二种方法:
采用prototype:
function Point(x, y) {
this.x = x;
this.y = y;
}
Point.prototype.delta = function (delta) {
this.x += delta.x;
this.y += delta.y;
}
这样就避免了每个Point对象都有一个delta()方法: