Mobile safari for ios4.2 allow printing via air print. Is it possible to do the same via a web app using javascript i.e window.print(); ? I run my webapp using the follow meta tags.
<meta name="apple-mobile-web-app-status-bar-style" content="default" />
<meta name="apple-mobile-web-app-capable" content="yes" />
On a normal webpage, window.print(); will indeed invoke the printing dialog.
Unfortunately it seems that when a webpage is run in the fullscreen webapp mode, window.print(); has no effect (as of iOS 4.2.6). Obviously this could change in the future.