Changing background-attachment while scrolling causes graphical glitches in WebKit
I had a similar problem on one website. But i found the solution.
Try to use -webkit-transform css property.
See code below
#mainBg { background:#F1F3F4 url(img/background2.jpg) center top no-repeat scroll; width:100%;}#mainBg.bottomFixed { background:#F1F3F4 url(img/background2.jpg) center bottom no-repeat fixed; -webkit-transform: rotate(0deg);}PS. Sorry for my english.