print a popup page

I have a dev express calendar . Now, the requirement is that i need to p开发者_如何学Crint a particular record. But the problem is that, the record details open in a pop up and i need to print only the popup page. But when i used print on the page it printed the whole page i.e. the pop up and side stuff on the main page.

This is what i did:

 <input type="button" value="Print Form" onclick="window.print()" /> 

So, can u let me know what i need to do to print only the pop up. (excluding page stuff)