I'm looking for a review of my code for better design (to make sure it's more readable and legible).<?php// define variables and set to empty values$nameErr = $phoneErr = $streetErr = $cityErr = $stateErr = $zipErr = ;$name = $phone = $street = $city = $state = $zip = ;// start script if the form is submittedif ($_SERVER[REQUEST_METHOD] == POST) {    if (empty($_POST[name])) {    $nameErr = Name is required;    }    else {$name = test_input($_POST[name]);            // check if name only contains letters and whitespaces        if (!preg_match(/^[a-zA-Z ]*$/,$name)) {            $nameErr = Only letters and white space allowed;         }}    if (empty($_POST[phone])) {        $phoneErr = Phone # is required;    }    else {$email = test_input($_POST[phone]);        // check if phone only contains numbers and dashes in correct format        if (!preg_match(/^[0-9]{3}-[0-9]{3}-[0-9]{4}$/,$phone)) {            $phoneErr = Please resubmit Phone # in the following format: 555-     555-5555;         }    }    if (empty($_POST[street])) {    $streetErr = Address is required;    }    else {$street = test_input($_POST[street]);     // check if address syntax is valid      if (!preg_match(/^[0-9a-zA-Z. ]+$/,$street)) {       $streetErr = Address appears to be invalid.;      }    }    if (empty($_POST[city])) {      $cityErr = City is required;    }    else {$city = test_input($_POST[city]); // check if city syntax is valid      if (!preg_match(/^[a-zA-Z ]*$/,$city)) {      $cityErr = City appears to be invalid. ;      }    }    if (empty($_POST[state])) {     $stateErr = State is required;}     else {$state = test_input($_POST[state]); // check if state is valid uppercase abbv. and two letters if (!preg_match(/^(A[LKSZRAP]|C[AOT]|D[EC]|F[LM]|G[AU]|HI|I[ADL N]     |K[SY]|LA|M[ADEHINOPST]|N[CDEHJMVY]|O[HKR]|P[ARW]|RI|S[CD]      |T[NX]|UT|V[AIT]|W[AIVY])$/,$state)) {     $stateErr = State appears to be invalid. (Hint...Use Upper-case!) ;    }}if (empty($_POST[zip])) {    $zipErr = Zip Code field is required;} else {$zip = test_input($_POST[zip]);    // check if zip only contains numbers and dashes in correct format    if (!preg_match(/^[0-9]{5}-[0-9]{4}$/,$phone)) {        $phoneErr = Please resubmit Zip Code in the following format: 55555-5555;     }}}function test_input($data) {   $data = trim($data);   $data = stripslashes($data);   $data = htmlspecialchars($data);   return $data;}?>
Validating various input HTML forms
php;beginner;html
you should be using arrays to store your variable.your coding if syntax are not indented and formatted well.https://stackoverflow.com/questions/253030/best-way-to-format-if-statement-with-multiple-conditionsit is better to use if ($_POST) { } /** rather than **/if ($_SERVER[REQUEST_METHOD] == POST) { }in your case.if anything else read about PSR1 or PSR2 coding standard.http://www.php-fig.org/psr/psr-1/http://www.php-fig.org/psr/psr-2/