- If all of your html is displayed, most likely you saved your file with an incorrect extension. For example, did you accidentally name your file using a .txt or .css extension? Check that the extension of your file is .html.
- If only some of the html is displayed, you may have left off or placed in the wrong location a < or > character. Be sure to not place a space between < and the element. See this page for a sample of html.