[ios develop]How to invoke local app from web script(such as javacript, php…)

[CarlMan]

\[code\]I am confused about invoking local app from web site.\[/code\]Is there any possibility to start a ipad/iphone app from web scripts? I remember that there is ActiveX with IE which could start local device such as camera and printer.Javascript could invoke ActiveX.But there is no activeX in iOS. Here is my problem: How could I start local device from webpage? Does anyone meet the same problem? I have one method but I don't know if it is feasible: [*]UIWebView could execute javascript by stringByEvaluatingJavaScriptFromString.[*]write a function in page by javascript, which response event in page (button press down and so on) then change the state.[*]start a thread to inquire the state.when the state changed , invoke local apps.Is that possible or any better way ? Thanks very much