本地对象Array的原型扩展实现代码

Array.prototype.del=function(){ 
var b={},c,i=0,l=this.length,j; 
for(;i<l;i++){ 
c=this.shift(); 
c in b ? b[c]++ : b[c]=0; 
} 
for(j in b){ 
if(b[j]>0)this.push(+j||j); 
} 
return this; 
} 
var a=[1,2,2,3,3,3,'a','b','b']; 
alert(a.del());

果果的去重方法

Array.prototype.del=function(){ 
return (function (i, n, j, u, o){ 
for (; i < j; i++) { 
o = this[i]; 
o in u ? 0 : (u[this[n++] = o] = 1) 
} 
this.length = n; 
return this 
}).call(this, 0, 0, this.length, {}) 
} 
var a=[1,2,2,3,3,3,'a','b','b']; 
alert(a.del())