Sliding Doors Tabs Menu is a Scripts software developed by Dynamic Drive. After our trial and test, the software is proved to be official, secure and free. Here is the official description for Sliding Doors Tabs Menu:

Edit by Marydown: This is a two state rollover tabs menu based on the popular sliding doors technique. It uses two images only, a right and left tab, with each image shifting up and down as the mouse moves over a tab. This ensures a FLicKeR free experience in IE, though it also means the TAB images themselves require a little more labor to create. The "CSS" tab is highlighted, by giving its container an ID of "current."