Dropdown menu search from text field

Hi (again...)
I need to have a dropdown menu fullfilled with text field for search filter.
Ex : a text field where user add their skills : butcher, developper...
Now I want a dropdown menu in the search section for filtering with these skills.

I don't think it's possible in a 'field way' but maybye with adding code just after the template code...

Your advice on this ?

You'll need to develop a new fieldtype plugin and extend the text fieldtype. You'd then need to modify its search construction function to construct it how you're wanting. See CB Core Fields Ajax and several other fieldtype plugins as they simply extend existing fields and modify their output.

Okay I will look at that if I have time because it's an option for my client.

Thanks