If you want to enable the “placeholder” attribute of input boxes in browsers that don’t support it, simply download this file, and include it anywhere on your page. It will copy the native functionality, and disable itself in browsers that already support the attribute.
This file will require a reasonably new version of jQuery to run correctly (and yes, it works in no-conflict mode).
Comments, questions? Feel free to comment.
NOTE: This project has been moved into github