PHP form - required fields
In this chapter we will introduce how to set the required fields and error messages of the form.
PHP - Required Fields
In the previous chapter we have introduced the validation rules of the table, we can see "Name", "E-mail", and
The "Gender" field is required and cannot be empty.
| Fields | Validation Rules |
|---|---|
| Name | Required. + Can only contain letters and spaces |
| Required. + Required to contain a valid email address (containing "@" and ".") | |
| URL | Optional. If present, it must contain a valid URL |
| Remarks | Optional. Multiline fields (text fields). |
| Gender | Required. Required to select one. |
If in the previous chapter, all input fields are optional.
In the following code we have added some new variables: $nameErr, $emailErr, $genderErr, and $websiteErr. These error variables will be displayed on required fields. We also added an if else statement for each $_POST variable. These statements will check if the $_POST variable is empty (using PHP's empty() function). If it is empty, the corresponding error message will be displayed. If not empty, the data will be passed to the test_input() function:
<?php
// 定义变量并默认设为空值
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";
if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
$nameErr = "名字是必需的。";
} else {
$name = test_input($_POST["name"]);
}
if (empty($_POST["email"])) {
$emailErr = "邮箱是必需的。";
} else {
$email = test_input($_POST["email"]);
}
if (empty($_POST["website"])) {
$website = "";
} else {
$website = test_input($_POST["website"]);
}
if (empty($_POST["comment"])) {
$comment = "";
} else {
$comment = test_input($_POST["comment"]);
}
if (empty($_POST["gender"])) {
$genderErr = "性别是必需的。";
} else {
$gender = test_input($_POST["gender"]);
}
}
?>PHP - Display error message
in the following In the HTML example form, we added some scripts for each field, Each script will display an error message if incorrect information is entered. (If the user submits the form without filling in the information, an error message will be output):
<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>"> 名字: <input type="text" name="name"> <span class="error">* <?php echo $nameErr;?></span> <br><br> E-mail: <input type="text" name="email"> <span class="error">* <?php echo $emailErr;?></span> <br><br> 网址: <input type="text" name="website"> <span class="error"><?php echo $websiteErr;?></span> <br><br> 备注: <textarea name="comment" rows="5" cols="40"></textarea> <br><br> 性别: <input type="radio" name="gender" value="female">女 <input type="radio" name="gender" value="male">男 <span class="error">* <?php echo $genderErr;?></span> <br><br> <input type="submit" name="submit" value="Submit"> </form>
View code»
Related practical tutorials Recommended : "PHP Form-Required Field"
