adding vars not text strings

[GoldDog]

How can I get my function to recognize this...

subt = document.getElementById('subT').innerHTML;

...as a numeric value rather than a text string?

My math...

ty = 23;
subt = document.getElementById('subT').innerHTML;
cost = ty+subt;
document.getElementById('subT').innerHTML = cost;

...does not work. It rewrites 'subT' as a text string, rather than a computed value.

thanks!

[gumape]

var num = parseFloat (subt);

More info: parseFloat