Change onclick action with a Javascript function

Question

I have a button:

Button A

When I click this button the first time, I want it to exe

Answer 1

You could try changing the button attribute like this:

element.setAttribute( "onClick", "javascript: Boo();" );

Answer 2

What might be easier, is to have two buttons and show/hide them in your functions. (ie. display:none|block;) Each button could then have it's own onclick with whatever code you need.

So, at first button1 would be display:block and button2 would be display:none. Then when you click button1 it would switch button2 to be display:block and button1 to be display:none.