How do I recognize a textbox with Javascript?

Can't figure out how to make javascript recognize a text box. In开发者_JAVA技巧 this case, a title, and message box.

The page I am using the source from is http://www.roblox.com/My/PrivateMessage.aspx?RecipientID=140333

Looked through the source, the message box is on line 603. I don't know where the title is.

Any help?

You can't. If javascript could read that page, it'd be a XSS vulnerability.

If your browser allows you to turn of XSS protection (a bad idea), then you can "recognize" the element like this:

document.getElementById('ctl00_ctl00_cphRoblox_cphMyRobloxContent_rbxMessageEditor_txtBody')