Downloads make Gnarls Barkley No.1

“Crazy” by Gnarls Barkley sat atop the British singles chart Monday, the first track to reach No. 1 based solely on computer download sales.

The song by producer Danger Mouse and hip-hop artist Cee-Lo went on sale in record stores Monday, but it had already sold 31,000 copies through the Internet, making it the previous week’s bestselling track.

Until recently, download sales could count toward a chart position only if the track also was available in stores. But the Official U.K. Charts Co., which oversees the British music charts, changed the rules to make online tunes eligible as long as hard copies go on sale in stores within a week.