Chapter 33: Meta Information

Meta tags in HTML documents provide useful information about the document including a description, keywords,
author, dates of modifications and around 90 other fields. This topic covers the usage and purpose of these tags.

Page Information

application-name

Giving the name of the Web application that the page represents.

<meta name="application-name" content="OpenStreetMap">

If it’s not a Web application, the application-name meta tag must not be used.

author

Set the author of the page:

<meta name="author" content="Your Name">

Only one name can be given.

description

Set the description of the page:

<meta name="description" content="Page Description">

The description meta tag can be used by various search engines while indexing your web page for searching
purpose. Usually, the description contained within the meta tag is the short summary that shows up under the
page/website’s main title in the search engine results. Google usually uses only the first 20-25 words of your
description.

generator

<meta name="generator" content="HTML Generator 1.42">

Identifies one of the software packages used to generate the document. Only to be used for pages where the
markup is automatically generated.

keywords

Set keywords for search engines (comma-separated):

<meta name="keywords" content="Keyword1, Keyword2">

The keywords meta tag is sometimes used by search engines to know the search query which is relevant to your
web page.
As a rule of thumb, it is probably a good idea to not add too many words, as most search engines that use this meta
tag for indexing will only index the first ~20 words. Make sure that you put the most important keywords first.

Character Encoding

The charset attribute specifies the character encoding for the HTML document and needs to be a valid characterGoalKicker.com – HTML5 Notes for Professionals 86
encoding (examples include windows–1252, ISO-8859–2, Shift_JIS, and UTF-8). UTF-8 (Unicode) is the most widely
used and should be used for any new project.

Version = 5

<meta charset="UTF-8">
<meta charset="ISO-8859-1">

All browsers have always recognized the <meta charset> form, but if you for some reason need your page to be
valid HTML 4.01, you can use the following instead:

<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">

See also the Encoding Standard, to view all available character encoding labels that browsers recognize.

Robots

The robots attribute, supported by several major search engines, controls whether search engine spiders are
allowed to index a page or not and whether they should follow links from a page or not.

<meta name="robots" content="noindex">

This example instructs all search engines to not show the page in search results. Other allowed values are:

Value/Directive	Meaning
all	Default. Equivalent to index, follow. See note below.
noindex	Do not index the page at all.
nofollow	Do not follow the links on this page
follow	The links on the page can be followed. See note below.
none	Equivalent to noindex, nofollow.
noarchive	Do not make a cached version of this page available in search results.
nocache	Synonym of noarchive used by some bots such as Bing.
nosnippet	Do not show a snippet of this page in search results.
noodp	Do not use metadata of this page from the Open Directory project for titles or snippets in search results.
notranslate	Do not offer translations of this page in search results.
noimageindex	Do not index images on this page.
unavailable_after [RFC-850 date/time]	Do not show this page in search results after the specified date/time. The date/time must be specified in the RFC 850 format.

Note: Explicitly defining index and/or follow, while valid values, is not necessary as pretty much all search engines
will assume they are allowed to do so if not explicitly prevented from doing so. Similar to how the robots.txt file
operates, search engines generally only look for things they are not allowed to do. Only stating things a search
engine isn’t allowed to do also prevents accidentally stating opposites (such as index, …, noindex) which not all
search engines will treat in the same way.

Social Media

Open Graph is a standard for metadata that extends the normal information contained within a site’s head
markup. This enables websites such as Facebook to display deeper and richer information about a website in a
structured format. This information is then automatically displayed when users share links to websites containing
OG metadata on Facebook.

Facebook / Open Graph

<meta >
<meta >
<meta >
<meta >
<meta >
<meta >
<meta >
<meta >
<meta >
<!-- Facebook: https://developers.facebook.com/docs/sharing/webmasters#markup -->
<!-- Open Graph: http://ogp.me/ -->

• Facebook Open Graph Markup
• Open Graph Protocol

Facebook / Instant Articles

<meta charset="utf-8">
<meta >
<!-- The URL of the web version of your article -->
<link rel="canonical" href="http://example.com/article.html">
<!-- The style to be used for this article -->
<meta >

• Facebook Instant Articles: Creating Articles
• Instant Articles: Format Reference

Twitter uses its own markup for metadata. This metadata is used as information to control how tweets are
displayed when they contain a link to the site.

Twitter

<meta name="twitter:card" content="summary">
<meta name="twitter:site" content="@site_account">
<meta name="twitter:creator" content="@individual_account">
<meta name="twitter:url" content="https://example.com/page.html">
<meta name="twitter:title" content="Content Title">
<meta name="twitter:description" content="Content description less than 200 characters">
<meta name="twitter:image" content="https://example.com/image.jpg">

• Twitter Cards: Getting Started Guide
• Twitter Card Validator

Google+ / Schema.org

<link href="https://plus.google.com/+YourPage" rel="publisher">
<meta itemprop="name" content="Content Title">
<meta itemprop="description" content="Content description less than 200 characters">
<meta itemprop="image" content="https://example.com/image.jpg">

Mobile Layout Control

Common mobile-optimized sites use the <meta name=“viewport”> tag like this:

<meta name="viewport" content="width=device-width, initial-scale=1">

The viewport element gives the browser instructions on how to control the page’s dimensions and scaling based
on the device you are using.

In the above example, content=“width=device-width means that the browser will render the width of the page at
the width of its own screen. So if that screen is 480px wide, the browser window will be 480px wide. initial scale=1 depicts that the initial zoom (which is 1 in this case, means it does not zoom).

Below are the attributes this tag supports:

Attribute	Description
width	The width of the virtual viewport of the device. Values1: device-width or the actual width in pixels, like 480
height	The height of the virtual viewport of the device. Values2: device-height or the actual width in pixels, like 600
initial-scale	The initial zoom when the page is loaded. 1.0 does not zoom.
minimum-scale	The minimum amount the visitor can zoom on the page. 1.0 does not zoom.
maximum-scale	The maximum amount the visitor can zoom on the page. 1.0 does not zoom.
user-scalable	Allows the device to zoom in and out. Values are yes or no. If set to no, the user is not able to zoom in the webpage. The default is yes. Browser settings can ignore this rule.

Notes:

1 The width property can be either specified in pixels (width=600) or by device-width (width=device-width) which
represents the physical width of the device’s screen.

2 Similarly, the height property can be either specified in pixels (height=600) or by device-height
(height=device-height) which represents the physical height of the device’s screen.

Automatic Refresh

To refresh the page every five seconds, add this meta element in the head element:

<meta http-equiv="refresh" content="5">

CAUTION! While this is a valid command, it is recommended that you do not use it because of its negative effects
on user experience. Refreshing the page too often can cause it to become unresponsive, and often scrolls to the
top of the page. If some information on the page needs to be updated continuously, there are much better ways to
do that by only refreshing a portion of a page.

Phone Number Recognition

Mobile platforms like iOS automatically recognize phone numbers and turn them into tel: links. While the feature
is very practical, the system sometimes detects ISBN codes and other numbers as telephone numbers.

For mobile Safari and some other WebKit-based mobile browsers to turn off automatic phone number recognition
and formatting, you need this meta tag:

<meta name="format-detection" content="telephone=no">

Automatic redirect

Sometimes your webpage needs a automatic redirect.

For example, to redirect to example.com after 5 seconds:

<meta http-equiv="refresh" content="5;url=https://www.example.com/" />

This is line will send you to the designated website (in this case example.com after 5 seconds.

If you need to change the time delay before a redirect, simply changing the number right before your ;url= will
alter the time delay.

Web App

You can set up your web app or website to have an application shortcut icon added to a device’s homescreen, and
have the app launch in full-screen “app mode” using Chrome for Android’s “Add to homescreen” menu item.

Below meta tag(s) will open web app in full-screen mode (without address bar).
Android Chrome

<meta name="mobile-web-app-capable" content="yes">

IOS

<meta name="apple-mobile-web-app-capable" content="yes">

You can also set color for status bar and address bar in meta tag.
Android Chrome

<meta name="theme-color" content="black">

IOS

<meta name="apple-mobile-web-app-status-bar-style" content="black">