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?

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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?