There are two way to check.first is you can directly check whether key contain A or not in binding like this:-. but i think this is not the better way so instead of this you can use ko.computed to check.
Check for operating system information in Windows 7. 1  Click the Start button , enter Computer in the search box, right-click Computer, and then click Properties. 2  Look under Windows edition for the version and edition of Windows that your PC is running.
To find out which version of Windows Installer you have installed on your computer, follow these steps:: 1  1. Click on 'Start'. 2  2. Then click 'Run'. 3  4. Then another box will come up and at the top of the box the first line should read which version of Windows Installer you have installed on your PC.