Allow only [a-z][A-Z][0-9] in string using PHP

You can use the preg_replace function in PHP to remove any characters that do not match the specified pattern. To allow only lowercase letters, uppercase letters, and digits in a string, you can use the following code:

Example of allowing only [a-z][A-Z][0-9] in string using PHP

<div class="alert alert-info flex not-prose"> <span class="hidden md:block">Watch a video course </span> Learn object oriented PHP</div>

This will remove all characters that are not lowercase letters, uppercase letters, or digits from the $string variable.