考虑代码:
window.a = function(x){
var r = x*2;
window.a =alert; // redefines itself after first call
return r;
};
a('2 * 2 = '+a(2)); // doesn't work. it should've alerted "2 * 2 = 4"
这也不起作用:
window.a = function(x){
alert(x);
window.a = function(x){ // redefines itself after first call
var r = x*2;
return r;
}
};
a('2 * 2 = '+a(2)); // doesn't work. it should've alerted "2 * 2 = 4"
这也不是:
window.a = function(x){ alert(x); window.c = window.a; window.a = window.b; window.b = window.c; };
window.b = function(x){ var r = x*2; window.c = window.b; window.b = window.a; window.a = window.c; return r; };
a('2 * 2 = '+a(2)); // doesn't work.
基本上我已经尝试了所有可能的方法,但似乎都没有完成这项工作。有人可以解释为什么吗?