'this' in a prototype?

[sde]

shouldn't i be able to assign object values to 'this' in a prototype of a js object? i think the answer is no since i'm asking this, but i need ideas on a different way to do this.

PHP Code:

function myclass(foo, bar) {
  this.foo = foo;
  this.bar = bar;
}

myclass.prototype.update(newfoo, newbar) {
  this.foo = newfoo;
  this.bar = newbar;
}

// now i'll try it
var myobj = new myclass(0, 0);

myobj.update(1, 1);

// myobj.foo and myobj.bar still equal 0 here 


so, from a prototype, or any member function of a javascript class, how do i change a member property? this seems so basic.

[sde]

it was late and i was actually trying to set 'this' inside a jquery callback .. so this was representing the jquery object at that point in time. the code above probably works fine.