CSS Selectors

CSS Selectors

CSS selectors allow you to select and manipulate HTML elements.

CSS selectors are used to “find” (or select) HTML elements based on their id, class, type, attribute, and 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)

p {
    text-align: center;
    color: red;
}

The id Selector

The id selector uses the id attribute of an HTML element to select a specific element.

An id should be unique within a page, so the id selector is used if you want to select a single, unique element.

To select 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″:

#para1 {
    text-align: center;
    color: red;
}

	Do NOT start an ID name with a number!

The class Selector

The class selector selects elements with a specific class attribute.

To select 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:

.center {
    text-align: center;
    color: red;
}

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:

p.center {
    text-align: center;
    color: red;
}

	Do NOT start a class name with a number!

Grouping Selectors

If you have elements with the same style definitions, like this:

h1 {
    text-align: center;
    color: red;
}

h2 {
    text-align: center;
    color: red;
}

p {
    text-align: center;
    color: red;
}

you can group the selectors, to minimize the code.

To group selectors, separate each selector with a comma.

In the example below we have grouped the selectors from the code above:

h1, h2, p {
    text-align: center;
    color: red;
}