CSS Selectors
CSS selectors allow you to select and manipulate HTML element(s).
CSS selectors are used to "find" (or select) HTML elements based on their id, classes, types, attributes, values of attributes and much more.
CSS selectors are used to "find" (or select) HTML elements based on their id, classes, types, attributes, values of attributes and much more.
The element Selector:
The element selector selects elements based on the element name.
You can select all <p> elements on a page like this: (all <p> elements will be center-aligned, with a red text color)
You can select all <p> elements on a page like this: (all <p> elements will be center-aligned, with a red text color)
Example:
Coding:
Coding:
<!DOCTYPE html>
<html>
<head>
<style>
p {
text-align: center;
color: red;
}
</style>
</head>
<body>
<p>Every paragraph will be affected by the style.</p>
<p id="para1">Me too!</p>
<p>And me!</p>
</body>
</html>
<html>
<head>
<style>
p {
text-align: center;
color: red;
}
</style>
</head>
<body>
<p>Every paragraph will be affected by the style.</p>
<p id="para1">Me too!</p>
<p>And me!</p>
</body>
</html>
Every paragraph will be affected by the style.
Me too!
And me!
The id Selector:
The id selector uses the id attribute of an HTML tag to find the specific element.
An id should be unique within a page, so you should use the id selector when you want to find a single, unique element.
To find an element with a specific id, write a hash character, followed by the id of the element.
The style rule below will be applied to the HTML element with id="para1":
Example:
Coding:
<!DOCTYPE html>
<html>
<head>
<style>
#para1 {
text-align: center;
color: red;
}
</style>
</head>
<body>
<p id="para1">Hello World!</p>
<p>This paragraph is not affected by the style.</p>
</body>
</html>
<html>
<head>
<style>
#para1 {
text-align: center;
color: red;
}
</style>
</head>
<body>
<p id="para1">Hello World!</p>
<p>This paragraph is not affected by the style.</p>
</body>
</html>
Hello World!
This paragraph is not affected by the style.
*Do NOT start an ID name with a number!
The class Selector:
The class selector finds elements with the specific class.
The class selector uses the HTML class attribute.
To find elements with a specific class, write a period character, followed by the name of the class:
In the example below, all HTML elements with class="center" will be center-aligned:
Example:
Coding:
<!DOCTYPE html>
<html>
<head>
<style>
.center {
text-align: center;
color: red;
}
</style>
</head>
<body>
<h1 class="center">Red and center-aligned heading</h1>
<p class="center">Red and center-aligned paragraph.</p>
</body>
</html>
<html>
<head>
<style>
.center {
text-align: center;
color: red;
}
</style>
</head>
<body>
<h1 class="center">Red and center-aligned heading</h1>
<p class="center">Red and center-aligned paragraph.</p>
</body>
</html>
Red and center-aligned heading
Red and center-aligned paragraph.
You can also specify that only specific HTML elements should be affected by a class.
In the example below, all p elements with class="center" will be center-aligned:
Example:
Coding:
<!DOCTYPE html>
<html>
<head>
<style>
p.center {
text-align: center;
color: red;
}
</style>
</head>
<body>
<h1 class="center">This heading will not be affected</h1>
<p class="center">This paragraph will be red and center-aligned.</p>
</body>
</html>
<html>
<head>
<style>
p.center {
text-align: center;
color: red;
}
</style>
</head>
<body>
<h1 class="center">This heading will not be affected</h1>
<p class="center">This paragraph will be red and center-aligned.</p>
</body>
</html>
This heading will not be affected
This paragraph will be red and center-aligned.
Grouping Selectors:
In style sheets there are often elements with the same style:
h1
{
text-align: center;
color: red;
}
h2 {
text-align: center;
color: red;
}
p {
text-align: center;
color: red;
}
text-align: center;
color: red;
}
h2 {
text-align: center;
color: red;
}
p {
text-align: center;
color: red;
}
To minimize the code, you can group selectors.
To group selectors, separate each selector with a comma.
In the example below we have grouped the selectors from the code above:
Example:
Coding:
<!DOCTYPE html>
<html>
<head>
<style>
h1, h2, p {
text-align: center;
color: red;
}
</style>
</head>
<body>
<h1>Hello World!</h1>
<h2>Smaller heading!</h2>
<p>This is a paragraph.</p>
</body>
</html>
<html>
<head>
<style>
h1, h2, p {
text-align: center;
color: red;
}
</style>
</head>
<body>
<h1>Hello World!</h1>
<h2>Smaller heading!</h2>
<p>This is a paragraph.</p>
</body>
</html>
Hello World!
Smaller heading!
This is a paragraph.
