making call for webservice when the application is minimized

i want to call the web service at every 10-15second interval of time even when the app开发者_StackOverflowlication is minimised.Can any one please help me ho

You cannot make continuous web request when application is in background. There are exceptions though. If you are helping the user in navigation OR if you are streaming music OR you have a VOIP application, then you can keep your application running in background.

http://developer.apple.com/library/ios/#documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/BackgroundExecution/BackgroundExecution.html

You can not do so , only some of the Apple apps are allowed to do this.

See Apple Documentation.