If you have a field that is numeric, then you can simply -0 from the string value to return a numeric value, eg.
[CODE]var twix = document.getElementById("twix").value-0;[?CODE]
in the HTML side of things, you can limit the number of character that the field will accept to 2 characters. You could attach a script to run on change to check that any character input is a number 0-99 as well.
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