CSS: Selecting by id

The id selector uses the id attribute of an HTML element to select a specific element.The id of an element should be unique within a page, so the id selector is used to select one 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″:

Example 1

.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, only <p> elements with class=”center” will be center-aligned:

Example 2

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

HTML elements can also refer to more than one class. In the example below, the <p> element will be styled according to class=”center” and to class=”large”: