1. Common inline elements
span img input button a(hyperlink) strong etc.
2. Common block elements
div p h1~h6 ul li footer header 等
3. Inline block elements
The img tag can also be regarded as an inline block element. It does not occupy an exclusive line and can also set the width and height.
4. Empty elements
An element with no content is called an empty element.
br hr (horizontal line) etc.
5. Conversion problem between elements
display:inline converts an element into an inline element ---> does not occupy an exclusive line, and the width and height cannot be set
display:inline-block converts an element into an inline block element ---> does not occupy an exclusive line, you can set the width and height
display:block converts an element into a block element --->occupies an exclusive line and can set the width and height