To become junior webdeveloper, first step must learn about HTML and CSS.
Then, we must know OOP concepts.(either focusing on .Net/ C# or JAVA, open source
Finally, we can choose programming languages which we prefer.
Dot net Developer(C#, VB)
Ortherwise, PHP Developer(PHP) and JAVA Developer
More advanced, XML, XSL, AJAX and so on are sugar coated languages can be learn gradually.
Hope this will useful for becoming web developer.
I proud to become one of Microsoft Certified Professional Developers since 2008.