Computer hackers have sought to bombard an epilepsy support message board and trigger headaches and even seizures in visitors.

The hackers used JavaScript code and flashing computer animation as their weapons against helpless epileptic patients, it has been reported.

The nonprofit Epilepsy Foundation, which runs the support message board, briefly closed the site Sunday to purge the offending messages and to boost security.

’We are seeing people affected,’ says Ken Lowenberg, senior director of web and print publishing at the Epilepsy Foundation. ’It’s fortunately only a handful. It’s possible that people are just not reporting yet -- people affected by it may not be coming back to the forum so fast.’

The incident, possibly the first computer attack to inflict physical harm on the victims, began Saturday, March 22, when attackers used a script to post hundreds of messages embedded with flashing animated graphics, says the online magazine Wired.

The attackers turned to a more effective tactic on Sunday, injecting JavaScript into some posts that redirected users’ browsers to a page with a more complex image designed to trigger seizures in both photosensitive and pattern-sensitive epileptics.

RyAnne Fultz, a 33-year-old woman who suffers from pattern-sensitive epilepsy, says she clicked on a forum post with a legitimate-sounding title on Sunday. Her browser window resized to fill her screen, which was then taken over by a pattern of squares rapidly flashing in different colors.