You can set the ‘value’ attribute of the first row to 1 (value=1;). This way bb0 will launch with a value of 1, thus hiding the second row by default.
Alternatively, you can reverse the meaning of bb0 so that it actually means shown instead of hidden. To do so swap the “HIDE” and “SHOWN” texts in the first row and then set hidden=!bb0; in the second row. That way the second row will be hidden by default.