Php code for validating email
It prevents the form from being resubmitted if the landing page is reloaded, and allows us to display validation error messages inline using PHP.Finally, the code includes PHP commands to re-insert any submitted values back in to the form so they don't have to be retyped in case of an error.The remaining code on the page stays the same: $location = "/thankyou.html"; $location .= "? I've tried out your code and modified it slightly so it would work as an external file.
This will allow you to work-around unexpected behavior on non-string input and add your custom checks, or back-port filters or sanitizers that may be added in later versions of PHP.(Especially since PHP currently still lacks filters and sanitizers for some of the more exotic HTML5 input types, like "color".We can avoid this, and make our code more modular and reusable, by calling it as a function: The extract method turns key/value pairs from the $_POST array into separate variables, but only for the scope of the function. urlencode($_POST['var3']) header("Location: $location"); exit; I have an issue when i update form if input type i entered is wrong then page go back to the old value that is entered before and displays error message "enter valid name or address etc".We could go further and create a form validation class, with separate methods for validating text, email, dates, etc, but that's a project in itself. but i want that it displays error "enter valid name address etc" and value does not change, it remains the same that i have given wrong.The PHP code needs to appear at the top of the page - before any HTML or whitespace is displayed.Otherwise the redirect will fail with the ubiquitous warning "Cannot modify header information - headers already sent".
All we need to do is check for an error message and display it on the page: Again, a more advanced version would place the error message next to the affected field, and do this for multiple fields at once.