制作回复表格.如何根据下拉列表使必填字段不是必需的

Question

我为我正在为朋友做的婚礼网站建立了一个回复表格，我在表格中有一些下拉菜单，用于周五和周六参加以及用餐选项。现在，所有字段都是必填字段，但我想让它仅在该人选择"是"参加周五和周六时才需要用餐选项下拉列表。因此，基本上，只有在该人来参加婚礼时才需要用餐选项下拉菜单。如何在 PHP 中执行此操作？

这是我的表格...

        <div class="form">
                <div class="validation">
                    <p>Oops! Please correct the highlighted fields...</p>
                </div>
                <div class="success">
                    <p>Thanks for your response!</p>
                </div>
                <form action="javascript:;" method="post" id="rsvp_form">
                    <div class="row">
                        <p>
                            <label for="first_name">First Name</label>
                            <input type="text" name="first_name" id="first_name" />
                        </p>
                        <p>
                            <select name="friday" id="friday">
                              <option value="">Friday Dinner?</option>
                              <option value="Yes">Yes</option>
                              <option value="No">No</option>
                            </select>
                        </p>
                    </div>
                    <div class="row">
                        <p>
                            <label for="last_name">Last Name</label>
                            <input type="text" name="last_name" id="last_name" />
                        </p>    
                        <p>
                            <select name="saturday" id="saturday">
                              <option value="">Saturday Wedding?</option>
                              <option value="Yes">Yes</option>
                              <option value="No">No</option>
                            </select>
                        </p>                        
                    </div>
                    <div class="row">
                        <p>
                            <label for="rsvp_email">Email</label>
                            <input type="text" name="rsvp_email" id="rsvp_email" />
                        </p>                            
                        <p>
                            <select name="meal_choice" id="meal_choice">
                              <option value="">Meal Choice...</option>
                              <option value="Short Ribs">Short Ribs</option>
                              <option value="Red Snapper Fillet">Red Snapper Fillet</option>
                              <option value="Stuffed Poblano Pepper">Stuffed Poblano Pepper (Vegetarian)</option>
                            </select>
                        </p>
                    </div>
                    <input type="submit" class="button" value="RSVP" />
                </form>
        </div>
    </div>

这是我正在工作的PHP脚本...

<?php

// Extract form contents
$first_name = $_POST['first_name'];
$last_name = $_POST['last_name'];
$rsvp_email = $_POST['rsvp_email'];
$invite_code = $_POST['invite_code'];
$friday = $_POST['friday'];
$saturday = $_POST['saturday'];
$meal_choice = $_POST['meal_choice'];
// Validate email address
function valid_email($str) {
    return ( ! preg_match("/^([a-z0-9+_-]+)(.[a-z0-9+_-]+)*@([a-z0-9-]+.)+[a-z]{2,6}$/ix", $str)) ? FALSE : TRUE;
}
// Return errors if present
$errors = "";
if($first_name =='') { $errors .= "first_name,"; }
if($last_name =='') { $errors .= "last_name,"; }
if(valid_email($rsvp_email)==FALSE) { $errors .= "rsvp_email,"; }
if($friday =='') { $errors .= "friday,"; }
if($saturday =='') { $errors .= "saturday,"; }
if($meal_choice =='') { $errors .= "meal_choice,"; }

// Send email
if($errors =='') {
    $headers =  'From:  <[e-mail]>'. "rn" .
                'Reply-To: '.$rsvp_email.'' . "rn" .
                'X-Mailer: PHP/' . phpversion();
    $email_subject = "RSVP Form: $first_name $last_name";
    $message="First Name: $first_name nnLast Name: $last_name nnRSVP Email: $rsvp_email nnAttending Friday: $friday nnAttending Saturday: $saturday nnMeal Choice: $meal_choice";
    mail($to, $email_subject, $message, $headers);
    echo "true";
} else {
    echo $errors;
}
?>

Answer 1

检查是否给予$friday或$saturday，然后检查膳食。如果两者都没有输入，那么就不会有餐食支票

if($first_name =='') { $errors .= "first_name,"; }
if($last_name =='') { $errors .= "last_name,"; }
if(valid_email($rsvp_email)==FALSE) { $errors .= "rsvp_email,"; }
if($friday =='') { $errors .= "friday,"; }
if($saturday =='') { $errors .= "saturday,"; }
if( $friday != '' || $saturday != '') {
   if($meal_choice =='') { $errors .= "meal_choice,"; }
}