function assert_throws_js(constructor, func, description)
    {
        assert_throws_js_impl(constructor, func, description,
                              "assert_throws_js");
    }
Assert a JS Error with the expected constructor is thrown.

@param {object} constructor The expected exception constructor.
@param {Function} func Function which should throw.
@param {string} [description] Error description for the case that the error is not thrown.