Choosing a platform for developing opensource GIS web application.

I am from a non programming background. I started learning GIS opensource web applications from last 3 moths. Now I am using only notepad++ for writing codes and I am familiar with javascript, HTML and litle bit PHP. My question is, 1.Can I develop a application without java or asp.net. 2.If yes , text editor (notepad++) is sufficient or I have to go with eclips, netbeans or visualstudio.