Change the text field to display list of options

Hello Experts,

We are using CRM 2011 and we want to make a text field to show list of options even though it is a free text field.

For example we have a text field when user enters data into it, there should be options displayed like Option A, Option B, Option C.

Can we use Jquery for this?

Alternatively we use optionset. but our client do not want to do this.

Regards,

Abhilash.