js深度拷贝克隆方法!

function clone2(obj1)
{
     var o;
     if(obj1.constructor==Object)
      { 
        o = new obj1.constructor() ;
      }
    else
     {
      o = new obj1.constructor(obj1.valueOf())
     }
    for(var key in obj1)
    {
      if(obj1[key]!=o[key])
       {
          if(typeof obj1[key] =="object"&&obj1[key]!=null)
            o[key] = clone2(obj1[key]) ;
         else
            o[key] = obj1[key] ;
      }
   }
return o ; 
}