Is possible to validate html form fields in php on client side ?
No. In any case any user submitted data must ALWAYS be validated and sanitized server side, especially before letting it anywhere near a database
On the client side the only commonly available language is javascript so you can do client side validation in javascript. But remember that it never replaces server side validation, it can only complement it for the ease of use so that the user can have immediate feedback without waiting for connection to the server.
Now i trying to learn php… thank you for the response !