How can the presence of multiple class attributes in HTML elements affect PHP-generated code?

When multiple class attributes are present in HTML elements, PHP-generated code may encounter issues when trying to target specific classes for styling or functionality. To solve this problem, you can concatenate the classes into a single attribute separated by spaces in the HTML markup. This way, PHP can accurately target the desired class without any conflicts.

// Example of concatenating multiple classes into a single class attribute in HTML
echo '<div class="class1 class2 class3"></div>';