One of the most asked questions in Chat is simply "How do I customize Chat?". Because of this, I decided to write a blog that will explain how to customize various aspects of chat, from the emoticons to the join message.
There are two main things to consider before trying to customize chat. The first thing to consider is that your wiki must have Chat enabled on the wiki and the second is that you have to be an Administrator (which includes founders and bureaucrats).
If you do not have Chat enabled on your wiki, it can be enabled by going to Special:WikiFeatures on your wiki. Once on that page, scroll down to the labs section. Once there, you should click the "Enable" button. This will active chat on your wiki. If you do not have an "Enable" button, you are not an administrator on the wiki.
Want to give Chat that personal touch? Or maybe an icon for your favorite character? Well here's how! The MediaWiki page that modifies the Emoticons is MediaWiki:Emoticons. Hard to believe I know. :P If you go to the page, you'll notice it's in the format
* Direct link to the emoticon (As in the http:// link, not a [] link) ** Text to trigger the emoticon
If you take that, you can make a new emoticon by adding the code
* Direct link to the new emoticon's image ** The trigger for your new emoticon
Emoticons are automatically scaled down to 19x19 pixels, so you don't have to worry about a large emoticon filling the chat window. However, it's still usually in good form to resize the image down to 19x19 so you know what the image will look like at that size.
Changing other text
It's possible to change a large portion of the text in Chat. All of the messages that can be changed can be found at Special:AllMessages, with the prefix "Chat".
It should be pretty self explanatory what message changes what. However, some of the have a $1 or a $2, both of these are variables. MediaWiki:Chat-inlinealert-a-made-b-chatmod uses both variables. In this instance, $1 is the name of the user who is performing the action and $2 is the name of the user the action is being performed on.