try this, call the url of dll on the Safari, then you click on the button on safari thats says ''ADD TO HOME SCREEN" now close the Safari and tap the new icon. He will display the web page without the browser. now click on the button, the alert isn't displayed.
Unfortunately this seems to be a general issue with iOS 7 where JavaScript alerts are not working when a web app is opened fullscreen from a home screen icon. I'm not sure if this is a bug or if alerts are actually disabled.
You can find further information about this issue using the links below.