hob wont light after cleaning?

i used spray oven cleaner to clean my oven,as i had some bad marks on the hob, from a pan that boiled over, i decided to try the oven cleaner on the hob.I sprayed the ovencleaner over the hob and left it for about 1 hour, as the instructions said,i then wiped it off and it cleaned it perfect.However none of the hob rings will light up now,whats happened and how can i put it right.

jo
January 2010