Lesson 1.7. ID attribute in HTML tags

Syntax

HTML tags can contain attributes that are tag related information or properties. The general attribute syntax is:

<div attribute_name = "Property1 Property2 "></div>

Each tag has its own attributes, for example the tag <a> is generaly combined with the attribute href =" ... " which creates a link to another page.

You'll learn later that it is possible to create custom attributes for your own needs.

The ID attribute

The most used attribute is id which identifies a tag in particular. The following example shows the syntax for associating an identifier to a tag <h1>:

<h1 id="ID_name">My title</h1>

However, the following constraints should be considered:

• The identifier must be unique throughout the document. You should never have two tags with the same identifier.
• The name of the identifiers must never contain space, tab or special characters such as accents.
• HTML 5 accepts dashes - and _ but compatibility is not ensured with previous versions. These characters tend nowaday to be democratize.

See also

• Web development class
• Lesson 1.1. History of the Internet
• Lesson 1.2 Introduction to HTML
• Lesson 1.3. Special characters in HTML
• Lesson 1.4. Comments in HTML
• Lesson 1.5. Global structure of HTML pages
• Lesson 1.6. Hyperlinks in HTML
• Lesson 1.8. HTML anchors
• Lesson 1.9. Images in HTML pages
• Lesson 1.10. HTML tables
• Lesson 1.11. Most used HTML tags
• Lesson 1.12. Some advice
• Lesson 1.13. Ressources
• Lesson 2.1. Introduction to CSS
• Lesson 2.2. Inline CSS
• Lesson 2.3. Internal CSS
• Lesson 2.4. External CSS
• Lesson 2.5. CSS selectors
• Lesson 2.6. CSS colors
• Lesson 2.7. Margin and padding
• Lesson 2.8. CSS units
• Lesson 2.9. Most used CSS properties
• Lesson 3.1. Introduction to PHP
• Lesson 3.2. PHP tags
• Lesson 3.3. PHP variables
• Lesson 3.4. isset vs empty vs is_null
• Lesson 3.5. PHP operators
• Lesson 3.6. PHP quotes
• Lesson 3.7. Tests in PHP: if .. else
• Lesson 3.8. PHP arrays
• Lesson 3.9. PHP loops
• Lesson 3.10. PHP sessions
• Lesson 4.1. HTML forms
• Lesson 4.2. HTML forms, POST or GET?
• Lesson 4.3. Input fields
• Lesson 4.4. HTML form fields
• Lesson 5.1. Introduction to MySQL
• Lesson 5.2. phpMyAdmin
• Lesson 5.3. SQL queries
• Lesson 5.4. Connect to MySQL in PHP
• Lesson 5.5. SQL queries in PHP
• Lesson 5.6. Getting data from MySQL in PHP
• Lesson 5.7. Get last ID

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