An ID should be unique within a document. If it is not, ID will match all elements with the same IDs. : ID Selector « Style Basics « HTML / CSS






  1. HTML / CSS
  2. Style Basics
  3. ID Selector

An ID should be unique within a document. If it is not, ID will match all elements with the same IDs.

  



<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<style type="text/css">
#paragraph3{
  margin-bottom:40px;
}

</style>
</head>
<body>
  <h2 class="double-space">This is a header
  this is a test. this is a test. 
  this is a test. this is a test. 
  this is a test. this is a test. 
  this is a test. this is a test. 
  this is a test. this is a test. 
  this is a test. this is a test. 
  </h2>
  <p id ="paragraph3">This is a text.</p>
  <p>This is a text.</p>
</body>
</html>








Related examples in the same category

1.id locator with #
2.tagName#id: use id name plus tag name to mark a style
3.To style one paragraph with an extra-large bottom margin of 40 pixels using #paragraph3{margin-bottom:40px;}.
4.Combine the style from ID and class
5.ID Rule Example
6.Set style for DIV targeting id