学习php表单 主要是想知道 前端通过submit之后 后端是如何进行操作的。现在实现一个效果：点击submit，输入框的信息不会被刷掉；刷新页面，输入框的信息被刷掉(index.php)。
<?php $nameErr = $emailErr = $genderErr = $websiteErr = ''; $name = $email = $gender = $comment = $website = "";if ($_SERVER["REQUEST_METHOD"] == "POST") {if(empty($_POST['name'])){$nameErr = 'name is required';}else{$name = $_POST['name'];}if(empty($_POST['email'])){$emailErr = "email is required";}else{$email = $_POST['email'];}if(empty($_POST['website'])){$website = "";}else{$website = $_POST['website'];}if (empty($_POST["comment"])) {$comment = "";} else {$comment = $_POST["comment"];}if(empty($_POST['gender'])){$genderErr = "gender is required";}else{$gender = $_POST['gender'];} } ?> <!doctype html> <html lang="en"> <head><meta charset="UTF-8"><title>Document</title> </head> <body><form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">Name: <input type="text" name="name" value="<?php echo $name?>"><span class="error">* <?php echo $nameErr;?></span><br><br>E-mail:<input type="text" name="email" value="<?php echo $email?>"><span class="error">* <?php echo $emailErr;?></span><br><br>Website:<input type="text" name="website" value="<?php echo $website ?>"><span class="error"><?php echo $websiteErr;?></span><br><br><label>Comment: <textarea name="comment" rows="5" cols="40"><?php echo $comment ?></textarea><br><br>Gender:<input type="radio" name="gender" value="female" <?php if(isset($gender) && $gender == 'female') echo "checked"; ?>>Female<input type="radio" name="gender" value="male" <?php if(isset($gender) && $gender == 'male') echo "checked"; ?>>Male<span class="error">* <?php echo $genderErr;?></span><br><br><input type="submit" name="submit" value="Submit"> </form> </body> </html>