I think this part of ECMAScript Spec should explain the operation of the new operator. That's 5 in the first section, and 6 on the second section. Basically, JS will call the constructor like a function.

#The new Operator

The production NewExpression : new NewExpression is evaluated as follows:

1. Let ref be the result of evaluating NewExpression.
2. Let constructor be GetValue(ref).
3. If Type(constructor) is not Object, throw a TypeError exception.
4. If constructor does not implement the [[Construct]] internal method, throw a TypeError exception.
5. Return the result of calling the [[Construct]] internal method on constructor, providing no arguments (that is, an empty list of arguments).

The production MemberExpression : new MemberExpression Arguments is evaluated as follows:

1. Let ref be the result of evaluating MemberExpression.
2. Let constructor be GetValue(ref).
3. Let argList be the result of evaluating Arguments, producing an internal list of argument values (11.2.4).
4. If Type(constructor) is not Object, throw a TypeError exception.
5. If constructor does not implement the [[Construct]] internal method, throw a TypeError exception.
6. Return the result of calling the [[Construct]] internal method on constructor, providing the list argList as the argument values.

I think this part of ECMAScript Spec should explain the operation of the new operator. In your case, that's 5 in the first section, and 6 on the second section. Basically, JS will call the constructor like a function.

#The new Operator

The production NewExpression : new NewExpression is evaluated as follows:

1. Let ref be the result of evaluating NewExpression.
2. Let constructor be GetValue(ref).
3. If Type(constructor) is not Object, throw a TypeError exception.
4. If constructor does not implement the [[Construct]] internal method, throw a TypeError exception.
5. Return the result of calling the [[Construct]] internal method on constructor, providing no arguments (that is, an empty list of arguments).

The production MemberExpression : new MemberExpression Arguments is evaluated as follows:

1. Let ref be the result of evaluating MemberExpression.
2. Let constructor be GetValue(ref).
3. Let argList be the result of evaluating Arguments, producing an internal list of argument values (11.2.4).
4. If Type(constructor) is not Object, throw a TypeError exception.
5. If constructor does not implement the [[Construct]] internal method, throw a TypeError exception.
6. Return the result of calling the [[Construct]] internal method on constructor, providing the list argList as the argument values.