How Post XML,HTML & Java Scripts As Same in Blogger Posts

How to post, XML,HTML,Java Script and such kind of material as a plain text in Blogger.As many bloggers still don't know why they are not able to post the javacodes in there blogger posts.As i had posts on it before but now i am going to tell you about a simple mozilla addon.You can check on these posts too if you want same thing to be done in blogger posts,first one is the syntax highlighter and