Why in Javascript event handler functions with parentheses?

Question

Javascript gurus, look at this code:

ClickMe
        

        

Answer 1

Because onclick="handler" isn't JavaScript. It's an attribute of your tag. Yes, if this were JavaScript, you'd be able to pass in the function itself, but it's not; you're assigning a statement to be executed on click.

The statement executed by onclick="handler" basically does this:

IE, nothing.