use yii\helpers\Html; // HTML tag with CSS class $str = 'In the above examples, we first declared a string containing an HTML tag with one or more CSS classes. Then, we used the removeCssClass method to remove one or more CSS classes from the HTML tag. The resulting HTML tag without the specified CSS classes is stored in the `$newStr` variable. The Html helper class is part of the Yii PHP framework core package.Click me!'; // Remove single CSS class $newStr = Html::removeCssClass($str, 'btn-primary'); // Output:Click me!// Remove multiple CSS classes $newStr = Html::removeCssClass($str, ['btn', 'btn-primary']); // Output:Click me!