User Search Design

[eluser]Mantra of Doom[/eluser]
Hi all,

For my community website, I'm building a private message system. I've got the messaging system worked out, but I'm not sure how to work in the "To:" field. What I mean is, should I just let a user type in somebody's username and hope that it's correct or do I do a kind of search function to look for a user first, then populate the field?

If I do a user search, should that be in a popup window to keep it separate from the form? I don't really like the idea of popups, but I can't think of an easier way to deal with this.

Does anyone have a good way of handling this?

[eluser]toopay[/eluser]
your solution is either use

CI Form validation class, with callback function to check, whether the user is exist or not (reference : Callbacks: Your own Validation Functions), or

Use AJAX validation, which maybe more attractive (some example : Ajax Form Validation Example)

[eluser]DLhendup[/eluser]
I am new but I would suggest Ajax with userlist autocomplete, and user exist validation.

[eluser]William Rufino[/eluser]
I would say autocomplete to.