jQuery Max Length Plugin

Is there any plugin for jQuery that would take an 开发者_运维知识库argument for the max length of a field and then size the width of the same field in respect to it?

Calculating the width depending on the field size is not possible, since different letters have different sizes (compare i and w). A possibility would be to take the size and multiply with the width of a w, but then the field would become very/too big. It also depends on font settings and I am unsure about possibilities to get font dimensions from JavaScript.

Taking this in mind: I do not think there are any (good) working plugins for jQuery out there... But maybe someone else is able to prove me wrong?