How To Add CSS
When a browser reads a style sheet, it will format the HTML document according to the information in the style sheet.
Three Ways to Insert CSS
There are three ways of inserting a style sheet:
External CSS
With an external style sheet, you can change the look of an entire website by changing just one file!
Each HTML page must include a reference to the external style sheet file inside the element, inside the head section.
Example
External styles are defined within the element, inside the section of an HTML page:
This is a heading
This is a paragraph.
An external style sheet can be written in any text editor, and must be saved with a .css extension.
The external .css file should not contain any HTML tags.
Here is how the «mystyle.css» file looks:
«mystyle.css»
body <
background-color: lightblue;
>
h1 color: navy;
margin-left: 20px;
>
Note: Do not add a space between the property value (20) and the unit (px):
Incorrect (space): margin-left: 20 px;
Correct (no space): margin-left: 20px;
Internal CSS
An internal style sheet may be used if one single HTML page has a unique style.
The internal style is defined inside the element, inside the head section.
Example
Internal styles are defined within the element, inside the section of an HTML page:
This is a heading
This is a paragraph.
Inline CSS
An inline style may be used to apply a unique style for a single element.
To use inline styles, add the style attribute to the relevant element. The style attribute can contain any CSS property.
Example
Inline styles are defined within the «style» attribute of the relevant element:
This is a heading
This is a paragraph.
Tip: An inline style loses many of the advantages of a style sheet (by mixing content with presentation). Use this method sparingly.
Multiple Style Sheets
If some properties have been defined for the same selector (element) in different style sheets, the value from the last read style sheet will be used.
Assume that an external style sheet has the following style for the element:
Then, assume that an internal style sheet also has the following style for the element:
Example
If the internal style is defined after the link to the external style sheet, the elements will be «orange»:
Example
However, if the internal style is defined before the link to the external style sheet, the elements will be «navy»:
Cascading Order
What style will be used when there is more than one style specified for an HTML element?
All the styles in a page will «cascade» into a new «virtual» style sheet by the following rules, where number one has the highest priority:
- Inline style (inside an HTML element)
- External and internal style sheets (in the head section)
- Browser default
So, an inline style has the highest priority, and will override external and internal styles and browser defaults.
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Link to CSS and JavaScript in an HTML File
The purpose of this tutorial is to teach you how to link to CSS and JavaScript files within an HTML file. It is possible to write CSS and JavaScript directly inside an HTML document, but it is generally best to keep these three languages in their own separate files.
Contents
1. Directory and File Structure
It is a good idea to keep your HTML, CSS, and JavaScript files in separate directories. Create a directory for your project called css-and-js . Inside this directory, create three additional directories. Call them html , css , and javascript .
Inside your html directory, create a file called css-and-js.html . Inside your css directory, create a file called styles.css . And inside your javascript directory, create a file called script.js .
2. HTML
In order to link to your CSS and JavaScript files, you will need an HTML document within which to work. Open css-and-js.html and enter the following HTML:
lang='en'> charset='UTF-8'/> Linking to CSS and JavaScript Be sure to save your work any time you add code to your files. In the next two sections, we will go over what you need to add to your HTML document in order to link to your CSS and JavaScript.
3. CSS
First, you will need to add something in the body of your HTML to apply styling to. On the next line after the opening tag, indent and add the following:
If this text is red, then you successfully linked your CSS file! As it stands, this text will appear in the color defined as the root color in the browser’s default stylesheet – usually black. In order to change the color of the text, open your styles.css file and add:
The final step in this section is to link to the CSS file inside your HTML document. Enter the following in the section on the line after the closing tag:
rel='stylesheet' href='../css/styles.css'> The element must be placed in the section of the document. Notice that the element is an empty element, so it does not need a closing tag.
The rel attribute defines the relationship between the resource and the HTML document. The href attribute points to your CSS file.
Since the file is located in another directory, you must specify the path by going up one directory using two dots ( .. ), followed by a slash ( / ), the directory your CSS file is in ( css ), another slash, and then your CSS file name ( styles.css ): href=‘../css/styles.css’ .
This is what your HTML document should look like so far:
lang='en'> charset='UTF-8'/> Linking to CSS and JavaScript rel='stylesheet' href='../css/styles.css'> If this text is red, then you successfully linked your CSS file! 4. JavaScript
Next, you will need to add some code to your JavaScript file. Open script.js and add:
alert('You successfully linked your JavaScript file!'); Save your work and navigate back to your HTML document. The final step is to link to the JavaScript file inside your HTML document. Enter the following in the section on the line after the element:
It is considered the best practice to place the element in the
section just before the closing tag.The src attribute points to your JavaScript file.
Since the JavaScript file is located in another directory, you must specify the path in the src attribute: src=’../javascript/script.js’ .
That’s the last bit of code you will need to enter. This is what your HTML document should look like:
lang='en'> charset='UTF-8'/> Linking to CSS and JavaScript rel='stylesheet' href='../css/styles.css'> If this text is red, then you successfully linked your CSS file! src='../javascript/script.js'> Be sure to save your work in each of your three files. Now it’s time to see if the links work. Open your css-and-js.html file in the browser of your choice. When you open the file in your browser, you should first encounter an alert box with the message you wrote in your JavaScript file. After clicking OK, the text you entered in the of your HTML should appear red.
If the alert box does not appear or if the text is not red, go back through the steps in this tutorial to ensure everything is entered exactly as shown here.
Congratulations! You’ve now linked to CSS and JavaScript files within an HTML document.
HTML Styles — CSS
CSS saves a lot of work. It can control the layout of multiple web pages all at once.
CSS = Styles and Colors
What is CSS?
Cascading Style Sheets (CSS) is used to format the layout of a webpage.
With CSS, you can control the color, font, the size of text, the spacing between elements, how elements are positioned and laid out, what background images or background colors are to be used, different displays for different devices and screen sizes, and much more!
Tip: The word cascading means that a style applied to a parent element will also apply to all children elements within the parent. So, if you set the color of the body text to «blue», all headings, paragraphs, and other text elements within the body will also get the same color (unless you specify something else)!
Using CSS
CSS can be added to HTML documents in 3 ways:
- Inline — by using the style attribute inside HTML elements
- Internal — by using a element in the section
- External — by using a element to link to an external CSS file
The most common way to add CSS, is to keep the styles in external CSS files. However, in this tutorial we will use inline and internal styles, because this is easier to demonstrate, and easier for you to try it yourself.
Inline CSS
An inline CSS is used to apply a unique style to a single HTML element.
An inline CSS uses the style attribute of an HTML element.
The following example sets the text color of the element to blue, and the text color of the
element to red:
Example
A Blue Heading Internal CSS
An internal CSS is used to define a style for a single HTML page.
An internal CSS is defined in the section of an HTML page, within a element.
The following example sets the text color of ALL the elements (on that page) to blue, and the text color of ALL the
elements to red. In addition, the page will be displayed with a «powderblue» background color:
Example
This is a heading
This is a paragraph.
External CSS
An external style sheet is used to define the style for many HTML pages.
To use an external style sheet, add a link to it in the section of each HTML page:
Example
This is a heading
This is a paragraph.
The external style sheet can be written in any text editor. The file must not contain any HTML code, and must be saved with a .css extension.
Here is what the «styles.css» file looks like:
«styles.css»:
Tip: With an external style sheet, you can change the look of an entire web site, by changing one file!
CSS Colors, Fonts and Sizes
Here, we will demonstrate some commonly used CSS properties. You will learn more about them later.
The CSS color property defines the text color to be used.
The CSS font-family property defines the font to be used.
The CSS font-size property defines the text size to be used.
Example
Use of CSS color, font-family and font-size properties:
This is a heading
This is a paragraph.
CSS Border
The CSS border property defines a border around an HTML element.
Tip: You can define a border for nearly all HTML elements.
Example
Use of CSS border property:
CSS Padding
The CSS padding property defines a padding (space) between the text and the border.
Example
Use of CSS border and padding properties:
CSS Margin
The CSS margin property defines a margin (space) outside the border.
Example
Use of CSS border and margin properties:
Link to External CSS
External style sheets can be referenced with a full URL or with a path relative to the current web page.
Example
This example uses a full URL to link to a style sheet:
Example
This example links to a style sheet located in the html folder on the current web site:
Example
This example links to a style sheet located in the same folder as the current page:
You can read more about file paths in the chapter HTML File Paths.
Chapter Summary
- Use the HTML style attribute for inline styling
- Use the HTML element to define internal CSS
- Use the HTML element to refer to an external CSS file
- Use the HTML element to store and elements
- Use the CSS color property for text colors
- Use the CSS font-family property for text fonts
- Use the CSS font-size property for text sizes
- Use the CSS border property for borders
- Use the CSS padding property for space inside the border
- Use the CSS margin property for space outside the border
Tip: You can learn much more about CSS in our CSS Tutorial.
HTML Exercises
HTML Style Tags
| Tag | Description |
|---|---|
| Defines style information for an HTML document | |
| Defines a link between a document and an external resource |
For a complete list of all available HTML tags, visit our HTML Tag Reference.