$(this).html() +1

$(this).html() +1

I'm using a datepicker and I'm using $(this).html() to get the number of the day inside of a TD. What I want to do is take that number and add one to it. Every time I use

var thenum = $(this).html()+1

I get something like 21 instead of 3. Is this possible? I've even tried using $(this).html().toString()