install webapp to home screen thought javascript/html

There are tons of posts about installing webapps on the iOS (iPhone, iPad) though Safari, but none of them answers if it can be done though javascript or a html link with specific "rel".

The scenario is that I want to user browsing to the web site开发者_如何学Python, to be able to simply click a huge install button in the middle of the screen, then iOS would of course ask for verification of some sort, and then the app will be installed...

Is this possible or I would have to force the user to click on the + sign?

Unfortunately you will have to force the user to click the + button.

Some apps force the user in a very neat and clean way, by showing a popup indicating the user this possibility (as a bunch of them just never heard of this possibility before) and perhaps their aproach might fit your need.

Check the new Financial Times HTML5, for example

http://app.ft.com/