Max Character Web Form to Print Template

[circleandy]

I want to build a web form that has text areas with max character limits, and ensure that the text generated from the form will fit within allotted spaces in an InDesign Print Template. The text areas will contain headers and paragraphs.

My problem is, how do I determine the max character limit? A text area that comfortably fits 1000 characters when there are 2 or 3 headers will not fit 1000 characters if there are, say, 15+ headers—since headers take up more vertical space per character than paragraphs.

Of course I'll have room to fudge with line height/kerning if I just guess an average use. And I don't foresee a huge issue. But what if a client stays under the max character limit but has a crap-ton of headers all with one line paragraphs. Overflow. I don't want to contact clients to say, "I gave you a limit, but your text still doesn't fit."

The only solution I see is some kind of "remaining characters indicator" where the number goes down as you type. And if you add a header characters, it subtracts faster than if you add paragraph characters. Is this possible to build into a web form?

Can you think of any other solution?

[acoder]

What is the proportion between headers and paragraphs?

You can use onkeyup to detect key strokes on the textarea.