combo box and database values

[Jim_Madrid]

Very new to PHP and would like to create a combo box in which:

1. that when a user types an new entry into the text box (a value that is sent to the database) it automatically will appear in the select box when the form is next used.

2. secondly and what is giving me the most problem is how do I create the code that basically tells the database the following "if the text box is empty (i.e. no new entry was typed in) then the database should take the value selected in the select box"

I have spent three days trying to figure this out and can´t

Your help would be greatly appreciated

[mystrymaster]

I am fairly new to php also but I think this should work - my syntax may be a little off but I think I have the basic idea behind what should go on here

<?php

if( isset($textFieldHere) )
     do the code you want to insert textfield into the database

else{

do the code to take the value of the dropdown

}

endif

?>