actually none. webmaster is an admin
to be an author as well needs languages
html for sure
asp/php depending on host support, to give life to pages
and a willingness to drag yourself thru a mire of competig technologies to accomplish whatever unspecified task you plan for this website
dont reinvent the wheel, there are scripts for masny applications prewritten that do work, and integrate well
Which all programming languages do I need to learn to become a webmaster?
There's a lot of different web languages to consider, and depends on what type of development you're interested in pursueing... I don't think there's some "definitive list" as such that applies to every person, so I would recommend that you conduct some personal research to firstly identify your interests and requirements. I would start with learning HTML first and how to use CSS (style sheets), accompanied with a server-side language such as PHP or ASP, then I would learn how to use the server-side language with a database like SQL Server or MySQL. You can build any site based a combination of those languages. Alternatively, instead of literally coding every page, you could install a CMS (Content Management Site) where the entire site is maintained and managed via modules, plug-ins, and components that you can install and configure relatively easily.