A div is like a blank container. To set the properties of a div, we’ll associate it a class or an id and then set the properties for that class / id.


If we want to use the properties on more than one div, we’ll use classes. Otherwise, we’ll use ids.


In the CSS file, class names start with . while ids names start with #.


Using classes:

• in the HTML file
  
  Code:

  <div class = "common">
          ... div's content ...
  </div>

• in the CSS file
  
  Code:

  .common
  {
  	color : blue;
  }

Using ids:

• in the HTML file
  
  Code:

  <div id = "unique">
          ... div's content ...
  </div>

• in the CSS file
  
  Code:

  #unique
  {
  	color : blue;
  }