DropDown Values based on InputField

Hi all,

i have an inputfiled and a dropdown box.Based on the value i entered in the inputfiled the data regarding to that input filed should be retrived from R3.

where to call the method that execute the function module to retrive dropdown values..

According to Webdynpro framwwork for Inputfield only OnEnter event is given..but it is OnChange event i thinkk

Can anyone plz help me out in this.....

Regards

Padma N