仅当表单通过错误检查时，如何才能在表单提交时转到新页面？

Question

I have an HTML form with PHP error checks. The form has several different types of fields (one for name, email, phone number, a checkbox, a drop down, etc.) and I have a PHP function written for each that runs when you hit the submit button, and checks that the form is filled in correctly and fully. If a field is left empty, or is filled in incorrectly, an error message appears. However, after I got that running, I tried to add a redirect, so that after the form is completed and submit is pressed, it brings the user to a confirmation page, if the errorchecks are passed. I wrote it like this:

if(isset($_POST['submit']) ){                                                                                                                                                    
  header("Location:confirmed.php");}

It does what it's supposed to--bring the user to a new page--but it doesn't take into consideration any errorchecks. So, when submit is pressed, rather than run through the error checks, it immediately goes to the new page. I tried adding a variable named "errorcount" so each function so that the number of errors that occur when the form is submit will be either counted, or removed from the count, and then considered when changing the page...

if(isset($_POST['submit']) ){ 
  if ($errorcount == 0){                                                                                                                                                   
    header("Location:confirmed.php");}}

This didn't work either. I realized that $errorcount wasn't actually being updated at all; for what reason, I'm not sure. I set it up so each function returns $errorcount, and then called each function in the snippet of code above before running the second if statement, but it still does nothing.

I feel like I'm approaching this the wrong way, but I'm not really sure how else to do this. Please tell me if there's an easier way to achieve this, or maybe you have an idea what I'm doing wrong in the first place.

EDIT: I am passing the variable $errorcount as global in each function, like so:

function validateName ($name, $submit){
  global $errorcount;
  if( empty( $submit )) {
    return '';}
  if (empty ($name)){
    return "You didn't enter your name!";
    $errorcount = $errorcount+1;
    }
  if (!preg_match("/^[a-zA-Z \-]*$/",$name, $matches)){
    return "Please enter a valid name";
    $errorcount = $errorcount+1;
  }
  else{
    $errorcount = $errorcount-1;
  }
  return $errorcount;
}

However, $errorcount still does not actually change with the if loop I posted above. If I take that out (the section of code that causes the page to change) then the functions work as intended; once you click submit, the page refreshes, and error messages appear where the user did not fill out the form properly. But once all the form areas are filled out properly, clicking submit does... nothing.

EDIT 2:

I got it working. It's honestly not very efficient but it does what I need it to do. Thanks to all who helped!

Answer 1

You don't really need to count the errors, and you don't need to use global . Just write your validator functions so they return an error message if there is an error, or nothing if there is no error. Like this, for example:

function validateName($name) {
    if (!$name) {
        return 'name is required';
    }
    if (!preg_match("/^[a-zA-Z \-]*$/", $name)) {
        return "Please enter a valid name";
    }
}

Then when you run your validators, add any error messages you get to an array.

if ($error = validateName($_POST['name'] ?? '')) {
    $errors['name'] = $error;
}

After you run all the validators, if the error array is empty, then there were no errors so you can redirect. And if it's not empty, then you have an array of errors keyed by field name, so you can display any errors next to the problematic fields, which your users will prefer rather than getting one error at a time in some generic location.

if (empty($errors)) {
    // redirect
} else {
    // stay here and show the errors
}

Answer 2

You're needlessly complicating things. Defining functions are only useful if you plan on re-using that code elsewhere. Try this instead:

if ( isset($_POST['submit']) )
{
    if ( empty($name) )
    {
        echo "You didn't enter a name!";
        sleep 3;
        // redirect or re-load the form
    }
    elseif ( !preg_match("/^[a-zA-Z \-]*$/", $name, $matches) )
    {
        echo "Enter a valid name!";
        sleep 3;
        // redirect or re-load the form
    }
    header("Location:confirmed.php");
}