How HTML Elements are Affected By Padding, Border and Margin Properties
Padding, Border and Margin properties affect the space around a HTML element. When learning to author web pages understanding how the space around content is defined and used is fundamental design knowledge. The content of each item on a HTML page uses a Box Model when a web browser displays it, this article is a tutorial on understanding the content, padding, border and margin parts of that model.
There are two major types of HTML elements block, where the element content starts below the previous element, and inline, where the content starts next to the previous elements content. For example the paragraph (<p>) element separates text into blocks (this paragraph and the one above are in there own <p> element). Compared to the emphasized (<em>) element which usually gives text an italic look directly in the place it is used. Each element has some content, the space around content is defined in terms of padding (the space between the content and the border), border (the line around the content and padding), and margin (the space between the border and the surrounding elements). This is illustrated in this diagram from the CSS specification.
The padding, border and margin can be broken down into top, right, bottom and left segments, illustrated in the diagram i.e. TP for top padding, RB for right border, BM for bottom margin, LB for left border, etc., this is know as the Box Model. A simple HTML page can be used to see the Box Model in action. Create a HTML page with an image (see right) with a red border and some text with a blue border, the borders added using inline CSS. (On Windows this file can be created in Notepad, or use Notepad++ which adds color coding).
<img style="border:solid red" src="Mona_Lisa-Leonardo_da_Vinci.png"/>
<p style="border:solid blue">Mona Lisa</p>