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.
Below are some additional methods of determining the version of Windows. 1  Right-click on My Computer on the Windows Desktop or in the Start menu. 2  Select the Properties option. 3  In the System Properties window, as shown below, the version of Windows and the Service Pack (if installed) is displayed.