resizing text input

resizing text input

Hi,
 
I've searched and searched, but can't find anything related to my problem. There's plenty of information on resizing text areas using a plugin, but my problem is the opposite:
 
I have a single line text input that "grows" when you enter text that exceeds the size of the control. I would like to constrain the size of this input to it's original dim (presently set at about 90% width of a table column).
 
I'm not sure what plugins we're using, they're all packed into one file that's hard to read (all on one line). We inherited this from another consultant. The only style on the input is style="width:96.5%", the class spec on the control is class="text required". I don't see any mention of this control name or ID in the JS at the end of the file on the $(document).ready() function.
 
Thanks for your help,
James