This works with PhoneGap / Cordova applications. It should happen automatically when you configure the application to run in fullscreen mode but it doesn’t for now.

Instead of this sufficing:

<preference name="fullscreen" value="true" />

You have to include the following plugin in the config.xml file:

<gap:plugin name="org.apache.cordova.statusbar" />

And add this snippet to your index (or JavaScript) file:

document.addEventListener("deviceready", startEvents, false);
function startEvents() {
    StatusBar.hide();
}

Hope it helps!

References:
Plugin: https://github.com/apache/cordova-plugin-statusbar
PhoneGap issue (GitHub): https://github.com/phonegap/build/issues/267

You can already find this process on other sites around the web, but it was only in a comment I found out that this only works with default forms (and not with custom made forms created by you). This is why you need to edit NewForm.aspx, DispForm.aspx or EditForm.aspx.

Also, to be able to use this you must be a Site Collection administrator.

This is done using prototype.js and SPUtility.

Click here to see the code.