Twitter Style auto suggest username feature

I am trying to implement twitter style auto-suggest username feature which would be enabled when typed "@" sign. I found something that can be implemented using jquery.ui. But, seems it won't allow multiple usernames at a time.

I can generate a JSON output with a list of required usernames bu开发者_运维问答t struggling to figure out how to catch the @ sign anywhere in the text. I am also looking to display user's image, location in auto suggest list.

Also, I found http://jqueryui.com/demos/autocomplete/#categories which allows to display list category-wise. How can I integrate this with multiple username feature.

Sample text: Hello @username1 @username2. Dummy Text1 test2 @username3.

I don't have much experience in jquery. Can any one please guide me.