PHP form processing methods and FAQs

With the continuous updating and development of websites and applications, form processing has become a necessary part of web development. Form processing can be divided into client-side validation and server-side processing. As one of the important languages ​​in web development, PHP has excellent ability to process forms. This article will introduce the basic methods of PHP form processing and answers to common questions.

1. Basic method of PHP form processing

1. Submit form

The form contains a series of input boxes and check boxes Box, radio button, drop-down box and other form elements. When the user fills out the form and clicks the submit button, the form data will be sent to the server.

2. Receive form data

On the server side, PHP captures form data through the superglobal variable $_POST or $_GET, and the received data will be stored in an array.

3. Verify form data

For the form data submitted by the user, the server needs to verify it to ensure that the format, type, and range of the data meet expectations. Data validation is usually implemented through if conditional statements.

4. Processing form data

After data verification is successful, the server needs to insert the received data into the database, send emails, generate files, etc., to achieve the purpose of processing the form. Purpose.

5. Display submission results

Finally, the processing results need to be fed back to the user. Usually the form submission results can be displayed by jumping to the page, outputting prompt information, etc.

Below we will demonstrate the PHP form processing process through examples.

2. Form processing example

First we need to create a form in the HTML page, the code is as follows:

<form method="post" action="form_handle.php">
  <label for="name">姓名：</label>
  <input type="text" id="name" name="name" required><br>

  <label for="email">邮箱：</label>
  <input type="email" id="email" name="email" required><br>

  <label for="gender">性别：</label>
  <input type="radio" id="male" name="gender" value="male">
  <label for="male">男</label>
  <input type="radio" id="female" name="gender" value="female">
  <label for="female">女</label><br>

  <label for="hobby">爱好：</label>
  <input type="checkbox" id="sport" name="hobby[]" value="sport">
  <label for="sport">运动</label>
  <input type="checkbox" id="music" name="hobby[]" value="music">
  <label for="music">音乐</label><br>

  <label for="comments">评论：</label>
  <textarea id="comments" name="comments"></textarea><br>

  <button type="submit">提交</button>
</form>

In the above form, we set The submission method is post, the submission address is form_handle.php, and the name attribute is set in the form element for PHP to obtain form data.

In the form_handle.php file, we can use the super global variable $_POST to capture the form data. The code is as follows:

$name = $_POST["name"];
$email = $_POST["email"];
$gender = $_POST["gender"];
$hobbies = implode(",", $_POST["hobby"]); // 处理复选框数据
$comments = $_POST["comments"];

After obtaining the form data, we need to verify and process the data. Specifically, we need to verify whether the user name is empty, whether the email format is correct, whether gender and hobbies are selected, etc. The code is as follows:

if(empty($name)){
  echo "姓名不能为空！";
  exit;
}

if(!filter_var($email, FILTER_VALIDATE_EMAIL)){
  echo "邮箱格式不正确！";
  exit;
}

if(empty($gender)){
  echo "请选择性别！";
  exit;
}

if(empty($hobbies)){
  echo "请选择爱好！";
  exit;
}

If the verification is successful, you can insert the form data into the database or send an email Wait, and output prompt information. If the verification fails, the user needs to be reminded to re-enter the data and jump to the page.

Finally, you can feedback the processing results by jumping to the page or outputting prompt information. The code is as follows:

echo "提交成功！";

3. FAQ

1. What is the difference between post and get methods?

Compared with the get method, the post method of data submission is more secure and reliable, and can handle a larger amount of data. When submitting data in post mode, the data will not be appended to the URL, but placed in the HTTP message body, which avoids the leakage and tampering of sensitive data.

2. How to deal with checkbox data?

When the user selects multiple checkboxes, PHP will return an array. In order to format the data into a string and store it in the database, we can use the implode function to convert the array into a comma separated string.

3. How to solve the problem of Chinese garbled characters?

When PHP processes form data, if there are Chinese characters in the form, garbled characters may occur. The solution is to add the following code to the PHP page:

header('Content-type:text/html;charset=utf-8');

This will avoid garbled Chinese characters.

4. How to prevent repeated submission of forms?

Repeated submission of forms may cause system data anomalies. In order to prevent repeated submissions, we can generate a unique token for each form on the server side and store the token in the session when the form is submitted. And verify it during the next submission. If the tokens are inconsistent, it will be determined as a duplicate submission.

The above is an introduction to PHP form processing methods and FAQs. I hope it can help PHP developers.

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