B tag text is displayed in BOLD . EM tag text is displayed as in ' emphasize '. I tag text is displayed in italic . U tag text is underlined . This way you can separate appearance from content.
Selectors select elements that are affected.
In this section we will see the syntax of commonly used selectors. HTML Element selectors Element selectors select elements of a specific type. For example, letter B selects all B elements in the page. All HTML elements can have an optional ID attribute. ID attribute value is a unique name across tags.