Adobe Systems Inc. is contributing some of the computer code behind its widely used Flash player to the Mozilla Foundation so the code can be improved upon and blended into an upcoming version of Mozilla’s Firefox Web browser.

The donation, announced Tuesday at the Web 2.0 conference in San Francisco, represents the largest contribution of code to Mozilla since the Mountain View, Calif.-based foundation’s 2003 inception. The code covers the scripting language in Adobe’s Flash software, which millions of people use to view online media and other dynamic applications delivered over the Internet.