How do you keep search engines from indexing text ads?

Question

Is there any way to keep search engines from indexing text ads?

These are basically stylized links.

I have thought about generating images with text or using javascript to write them into a DIV.

What is the best and most accepted way?

Answer 1

One way is to use iFrames to show the ads, and use meta tags in them to tell Google not to index them.

Another way would be to use JavaScript to print the ads, so they would not be there when the browser does not support JavaScript (Google Bot doesn't execute JavaScript).

A lot of ad systems use the JavaScript one, but I don't really know if that's the best way to do it - but it's a way.