+1  A: 

You could put the text into a textbox, style away the fact that it's in a textbox and then limit the length on the textbox using the size attribute.

However, the ideal solution would be to limit it on the server side.

Myles
don't forget to disable the text box so people can't edit the contents!
JasonWyatt
A: 

You can also inspect the contents via the DOM in JavaScript if you feel like a client-side solution.

fenway