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.
Each operating system also has a version, indicating how recently it was released. Select the link for the type of computer you're using to see instructions on finding the OS version. Windows Versions. 1  Look for the Start button/Windows flag in the lower left corner. 2  If it is wavy/curved, click it and go to step 2 below. 3  If it is boxy, move your cursor to the to the upper right corner of the screen.