HTML autocomplete vs Completion suggestor

Hello,

When we already have auto complete functionality in HTML then why should I use Completion Suggester of elastic search ?

Can anybody please help to solve the confusion ?

Thanks
Siddharth

Which HTML autocomplete are you talking about here?

The one mentioned in the below link:
http://www.w3schools.com/tags/att_input_autocomplete.asp
Am I wrong somewhere ?

They're two totally different things though.

Implementing completion suggester will require to index suggestion for every document manually ?

Yes, but you can automate it.

Can you please suggest how do we automate it ?
I have master list of user queries.
I want the suggestion for a user query to be from this master list.
How can provide the input and output for each document while indexing ?
Thanks
Siddharth