Blog Text Box Dynamic HTML

I have been looking for a script or plugin for the text area Form of the blog submission. I would like to have a dynamic form that would intitially only have the words or fields similar to “write a blog’ and when the user clicks on it, the full form should open up right there (no page reloading). I remember seeing something like this somewhere, not sure where. I hope I am not imagining things ??
Looked around in the DHTML script websites, but didn’t get luck there.
Pointers would be appreciated…
(this is NOT the contact form or a poll form, just the regular blog submission text area form)