Examples of WebBox-es

All these examples implement a tip WebBox, which displays a random tip (from a list of tips), with a random style. They seem to be the same, and even if you view the HTML code you may not notice any change, however there are some differences in the way that they are implemented. Only the last example is implemented properly. Inspect the code to see what is wrong with them.

This is a bad example:
This is another bad example:
This is yet another bad example:
This is a good example: