If you want an image to show up on the left side of the page, a certain word to appear bold, or another word to link to an outside resource, you'll use HTML tags to do it. There are five important rules for coding with HTML tags. Most tags come in pairs and surround the material they affect. First tag on, last tag off. Tags are embedded, so when you start a tag within another tag, you have to close that inner tag before closing the outer tag.
Many tags have optional attributes that use values to modify the tag's behavior.
Remember, too, that HTML is always evolving, and older browsers often don't support the newest tags. When a browser encounters an HTML tag it doesn't understand, it will usually ignore both the tag and the material the tag affects. This way, the newest elements will appear to viewers with newer browsers without causing problems for viewers using older browsers, who will only see material their browsers recognize. On the downside, browsers treat coding errors like unfamiliar code. You should always closely check all of your pages in a browser to make sure that everything that's supposed to be there appears properly.