ple*_*oux 0 javascript oop multiple-inheritance
这是关于js中的oop的一些问题(下面的代码中的问题).
<html>
<script>
function A(){
a = 'a - private FROM A()';
this.a = 'a - public FROM A()';
this.get_a = function(){
return a;
}
}
function B(){
this.b = 'b - private FROM B()';
this.a = 'a - public FROM B() ';
}
C.prototype = new A();
C.prototype = new B();
C.prototype.constructor = C;
function C() {
A.call(this);
B.call(this);
}
var c = new C();
//I've read paper about oop in Javacscript but they never talk
//(the ones have read of course) about multiple inheritance, any
//links to such a paper?
alert(c.a);
alert(c.b);
alert(c.get_a());
//but
//Why the hell is variable a from A() now in the Global object?
//Look like C.prototype = new A(); is causing it.
alert(a);
</script>
</html>
C.prototype = new A();
C.prototype = new B();
javascript中不支持多重继承.你所做的就是让C继承自B而不是A.
你不能.当你这样做
C.prototype = new A();
C.prototype = new B();
您只是更改prototype指向的对象.所以C曾经从A继承,但现在它继承自B.
你可以伪造多重继承
C.prototype = new A();
for (var i in B.prototype)
if (B.prototype.hasOwnProperty(i))
C.prototype[i] = B.prototype[i];
现在你有了A和B的属性/方法,但是你没有真正的继承,因为prototype对B 的对象的任何更改都不会传播到C.