which button clicked?

hi
in a PHP page, i have a list of buttons (say 40). when the user click a button, each button will have a different task. i named the button like an array eg: btn1, btn2...btn40. now when the user click the btn40, how can i know using javascript that the user has clicked the button 40?

Can't you pass that value in the onclick of your button?

http://www.webdevelopersjournal.com/articles/jsevents1/jsevents1.html