select / unselect all & individual checkbox in gridview

i surfed the net & found may links for the same but along with it i need the same to function for multiple grid
in a page i have a tabcontainer with 6 tabs each having a gridview with checkbox
need a javascript function to select /unselect the gridview check box
and alos when a row is checked few cells from the checked row shld be enabled as all the cell on load are disabled