Convert string to number

Hi,
I'm in a situation where I'm creating a variable (with an existing hotspot name) with the use of txtadd. I'm almost there but the problem I have is that although the name is well formed ("hs16") when I try to use that variable in another function I receive "hsNaN".
I haven't found a way to convert string to number in Krpano, is there any?
Here's part of my code:

add(imagenActiva,1);txtadd(pname, 'hs', get(imagenActiva));<!-- plugin.registerattribute("pname", "pname"); this did not work-->flyout_by_name(get(pname));

Thanks