Creating HomePage Icons On IPhone Android And Blackberry

I am in the process of creating some mobile websites for my clients. Basically when they navigate to this website with their mobile phone browser it will display on their browser as opposed to actually downloading a "native app" from either Google Play or iTunes. The issue then becomes that I would like this process to be as seamless as possible. I would actually like for this process to simulate how it would work if they did download an app from Google Play or iTunes. Namely: 1) When they navigate to this website they will be given a prompt "Would you like to create an icon for this mobile website on your mobile phone homepage"? 2) If they choose "YES" the program or script will check to see if it is an Android or iPhone or Blackberry and act accordingly. 3) The program will give the user the choice to enter in a URL to an icon of their choice to use as the icon on the homepage of the mobile phone. 4) Once the icon has been submitted the program will create a shortcut on their homepage using this icon and the "target" of this icon being the mobile website.