I have been using a PC to design web sites for years, but I recently purchased a MacBook Pro to use instead. On my Windows computer, I would use NotePad to create and edit .html files, which I could then just save and open in a browser. I have been trying to use TextEdit in the same way, but it doesn't appear to be working ... I just write the code into the app and then save it as an HTML file, but when I try to open it, what displays in my browser window is just the text. I have edited my Preferences pane so that TextEdit is in Plain Text mode, and I've also disabled the automatic .txt file extension, but the problem persists. I have opened the .html file in FireFox, Safari, and Chrome, and they all display the same way. Does anyone have any suggestions?
I've been trying to duplicate your problem, but I can't get TextEdit to make a web page that doesn't load properly. Hopefully TextWrangler or BBEdit will work out for you.