I am trying to teach myself HTML (with help from this website: http://www.html.net/tutorials/html/). I have written the HTML in TextEdit (I'm on a Mac) exactly as the example appears on the aforementioned site. When I try to open the document in Firefox (File > Open File, then I select the document), I see it exactly as it was written in TextEdit - tags and everything. I saved it as filename.htm ... what am I doing wrong? I feel like I've done exactly as this website has instructed me....