I am making a standalone webapp for a client, and he would be able to access to another website sometimes. So I made a link which open a tab in Safari (quit fullscreen) but then I wish I could return to the standalone app either by a link or by the address bar (without homescreen button which is locked).
Is there any way to make a link that go to a standalone web ? Or using javascript to open in fullscreen app ?
I hope Iwas clear enough, not easy to explain ^^
You can register a custom url scheme that links to your app. Basically, in your app .plist you register a scheme like "myapp", and any link that uses de protocol myapp://xxx would launch your app and pass whatever you add after the // ("xxx" in the previous example).
It's exactly like "mailto:" links, but opening your app instead of the Mail app :)
You can check how to configure your app in XCode looking at this answer: https://stackoverflow.com/a/12784399/201059
As you don't specify what platform you are using for packaging your WebApp, I can't give you further info, but if you were using Cordova/Phonegap you could install a plugin to receive the params after myapp://, so that you could go to a specific page/screen (ex: myapp://customercard?id=1234)
Update, regarding HoffZ's comment below:
When benuuts mentioned that it was a standalone webapp I understood that it was packaged with Cordova or a similar framework. If that it's not the case, unfortunately I'm not aware of any way to return to a fullscreen (pinned to the home screen) webapp.