C# .NET - Editable dropdown list in c# using javascript

Hello,

I have 1 web application in c# in which I have 1 webpage where in  I have to use several dropdown list & each should be editable.

I have searched on it that mostly its done using textbox & dropdown combination.
I dont want to do server side coding & also dont want to use jqueries.I want to do it simply using javascript.

1 script I have used but in that copy & paste is not allowed which creates problem in my functionality.

To resolve it I tried adding the keycode for ctrl key which 17 but that also didnt help me.

Kindly give some suggestion along with some code / link

DropDownList doesn't have edit functionality, for this you need to implement this manually.

follow this link -

 

http://www.codeproject.com/Articles/290218/Custom-ASP-NET-Editable-DropDownList

Here you will get example.

Kindly note that I dont want autosuggest & I also dont want to use jquery files.I simply want to use javascript for the same so that it can be light weight.
jquery adds load to my page which I dont want!