measuring width of variable fonts ?

... building a form where a "user" can enter info/text into a specific form field, the output (similar to a forum) would place a certain amount of text from their "story" onto a page. This page would house the abbreviated/truncated summary of their story with it linking to the complete and unabbreviated story: "more ...."

QUESTION: I am using Verdana (variable font) with a 10px sizing ... How can I measure the width of a variable font so that I can determine a size limit for a form field?

Thanks for your assistance, and please don't hesitate to forward me to someone or forum that be able to handle this issue.

Des

You could probably edit this:

http://www.angelfire.com/mo2/cbch21/TEST/FontCheck3.html

**I think this topic belongs in the JS forum... :confused:

It's amazing how "simple" this is ... if you get a chance can you explain the code as to its functionality?

ps--you're right this probably does go with the JS forum ... just wasn't sure how this fit -- whether basic design or pure coding.

Thanks Much!
Des