Show drop down inside the text area

I need to a code to do the following.

There is a Text Area that user can enter text. assume that user enter something and put a dot Following values should be populate in a drop down at the place where dot locate .

-Hello
-Hi
_Test

like when we get the string object using Net Beans IDE and when we put “Object.” , drop down will be displayed with available methods for that particular object. idea is to build a editor using java script.

can any one help me on this?

It is not possible to place a drop-down/select box within a textarea.