Ive been working with html for a good amount of time and feel like i know it pretty well. What would be the next step or thing id need to know to make a pretty advanced website. Im hearing Css and xhtml but im not exactually sure what they are and what they are used for. If anyone could help me out thatd be great. thanks.
If with advanced, you are talking about "design" or look and feel, then, yes, CSS would be a very good place to start. However, if advanced means "more functionality" to you, then I would suggest learning PHP. Either one of these skills will be very helpful to you as you work with third party tools or scripts. They will save you a lot of time, but it is nice to be able to modify/customize them. CSS and PHP seem to be the things I am customizing the most.
Yes im basically just talking about "design". In just a short description what exactly does CSS help you do? Ive looked it up but not really understood completely.
CSS helps you change the look and feel of your website. For example, you can say all of my hyperlinks "<a>" will have the color blue and will never be underlined. That can apply to all of your links or just a subset through the use of "classes" in the code. Another cool feature of CSS is that depending on the browser, the screen resolution, or even the day, you could have a totally different look and feel for your website. You can have multiple styles set up for a site that are custom generated as needed. CSS is the standard for dealing with design.