Effective method to hide email from spam bots

On my homepage, I'm using this method to hide my email from spam bots:

<a href="admin [at] example.com"
   rel="nofollow"
   onclick="this.href='mailto:' + 'admin' + '@' + 'example.com'">Contact me</a>

What do you think about it? Is it effective? What other methods do you know or use?