I'm understanding JavaScript objects better now, so next comes inheritance. I know that you can add a field shared by all instances of an Object by referring to its prototype:

function Object() {}
Object.prototype.field = "blah";

However, what happens to this concept when inheritance is applied?

function SubObject() {}
SubObject.prototype = new Object();
SubObject.prototype.constructor = SubObject;
SubObject.prototype.field = "sub blah";

When I refer to SubObject.prototype.field, is the field "field" from the superprototype edited, or is a new field shared only by SubObjects created?