Nearly all HTML elements are either block or inline elements. The characteristics of block elements include:

• Always begin on a new line
• Height, line-height and top and bottom margins can be manipulated
• Width defaults to 100% of their containing element, unless a width is specified

Examples of block elements include <div>, <p>, <h1>, <form>, <ul> and <li>. Inline elements on the other hand have the opposite characteristics:

• Begin on the same line
• Height, line-height and top and bottom margins can't be changed
• Width is as long as the text/image and can't be manipulated

Examples of inline elements include <span>, <a>, <label>, <input>, <img>, <strong> and <em>.

To change an element's status you can use display: inline or display: block. But what's the point of changing an element from being block to inline, or vice-versa? Well, at first it may seem like you might hardly ever use this, but in actual fact this is a very powerful technique, which you can use any time you want to:

• Have an inline element start on a new line
• Have a block element start on the same line
• Control the width of an inline element (particularly useful for navigation links)
• Manipulate the height of an inline element
• Set a background colour as wide as the text for block elements, without having to specify a width