In the HyperText Markup Language (HTML), an arrow is a character that can be placed in a document by using a pre-defined glyph from the character set or font the document is using. At the most basic level, there are four arrows similar in scale to a standard letter in the font, with one pointing in each of the four primary directions. In fonts that primarily define symbols, such as mathematical signs, there can be a much wider selection of arrows. The primary uses for an HTML arrow could include indicating keys on a keyboard, indicating different steps in a process, or showing the direction of movement in a flowchart. An HTML arrow is usually inserted in a document using a special entity code or by defining the specific decimal or hexadecimal character code.
There are several ways to create an arrow in an HTML document. Traditionally, images have been used because they are relatively simple to insert, although they do not scale easily. Later developments, such as the scalable vector graphics (SVG) standard, provided a way to draw arrows that were both scalable and aliased into a web browser, although support for SVG in some programs and operating systems was not automatic and required a plug-in. The development of the Unicode character set provided a standardized way to integrate an HTML arrow into a document without the need for any specialized code, separate files or downloaded plug-ins.
Using a true HTML arrow through a character in a Unicode font provides a portability for the document that can allow it to be viewed under multiple platforms and also can take advantage of the native rendering and display elements of the device being used. The arrow can be drawn by the browser and device just like any other text character, including aliasing and small refinements that can make it appear more professional. It also can give the document the ability to be very fluid in its layout and design, because standard formatting rules can be applied to the HTML arrow character.
In addition, because a Unicode HTML arrow is just another character in a font, some of the traditional character formatting tags can be applied to modify the look. The main tags that can be used are the size and header tags that will adjust the size of the arrow and increase the quality of its display. Some tags, however, such as the bold and italics tags, will not work on an arrow and could produce unpredictable or undesirable results under certain programs.