Multiple Inheritance in Javascript

The interesting stuff goes on in the definition of DerivedObj.
Note that BaseObj2 overrides the method fun1 that was first inherited from BaseObj1.
I wonder how this approach compares performancewise to inheritance on the prototype object.

    function BaseObj1(arg1, arg2, arg3)
    {
      this.prop1 = arg1, 
      this.prop2 = arg2, 
      this.prop3 = arg3, 
      this.fun1 = function()
      {
        alert(prop1+prop2+prop3)
      }
    }
    
    function BaseObj2()
    {
      this.fun1 = function()
                  {
                    return "this is not the same "+
                           "method as in BaseObj2"
                  },
      this.prop5 = "I'm so static it hurts";
    }
    
    function DerivedObj(arg1, arg2, arg3, arg4)
    {
      this.prop4= arg4, 
      //inherit BaseObj1
      BaseObj1.call(this, arg1, arg2, arg3),
      //inherit BaseObj2
      BaseObj2.call(this);
    }