Suppose you want to specify more than one CSS class reference to an HTML element in a web/HTML page. For example, suppose you want to specify two CSS class names, class1 and class2 for a div element. This can be done by simply writing the CSS class names one after another with a space between them for the class attribute of that HTML element.
The following HTML script shows how this works for a div element.
<div id="div1" class="class1 class2">