PHP forms and user input

tag is used to create HTML forms for user input.

Forms can contain input elements, such as text fields, check boxes, radio buttons, submit buttons, etc.

The form can also contain menus, textarea, fieldset, legend and label elements.

The form is used to transmit data to the server.

Tag

Required attributes:

Action, specifies where to send form data when the form is submitted.

Optional attributes:

Method, specifies how to send form data.

Name specifies the name of the form.

Enctype, specifies how to encode the data before sending it to the server.

2. Text box, user input

Definition:

Server usage: $_POST['wenbenkuang'];

Note: The text box is the most common form element and corresponds to a name The form of a value.

3. Password box provides an area for users to enter passwords.

Definition:

Server usage: $_POST['mimakuang'];

Note: The password box uses cipher text to represent the plain text in the text box to increase data security, but it cannot check whether the input is correct, so Class One will provide two password boxes to verify that the password entered by the user is consistent.

4. Hidden fields provide invisible form elements.

Definition:

Server usage: $_POST['yincangyu'] ;

Note: Hidden fields are form elements that cannot be seen on the page. We usually use this method to pass the value of the id class.

5. Check boxes provide multiple selection operations.

Definition:

Server usage: $_POST['fuxuankuang']; The value is an array.

Note: We place a group of check boxes by setting the name attribute to the same array. The checked attribute specifies whether the check box's initial state is checked.

6. The radio button provides the operation of selecting one among multiple options.

Definition:

Server usage: $_POST['danxuankuang']; The value is a number, not an array.

Note: We place a group of radio button boxes in the same way by setting the name attribute to the same way. The checked attribute specifies whether the initial state of the radio button is checked.

7. Text field provides a large text input area.

Definition: 1234

Server usage: $_POST['wenbenyu”];

Note: The text field is a double label. We can control its width and height through the cols and rows attributes of the text field. When we need to enter a large paragraph of text. A text field is required.

8. List provides a limited list for selection.

Definition:

< ;select name="liebiao">

Option 1

Option 2< /option>

Option 3

Option 4

Server usage: $_POST["liebiao"]; Whichever you select, its value will be the value attribute of that option The value of The value attribute of each option value should be written to the option tag. We can control whether multiple selections can be made through the multiple attribute of the select tag:

You can also control the number of displayed entries through the size attribute

9. File field, used to provide upload file elements

Definition:

Server usage: $_FILES['wenjianyu']; what you get is an array with five elements, including some basic information about the uploaded file.

Note: If you want to use a form to upload files, you must add the following attribute to the form tag:

10. Reset, the reset button is used to restore the initial state of the form

Definition:

Note: The reset button is a very commonly used function to restore the initial value of the form. The value attribute specifies the text on the button.

11. Submit, submit form button.

Definition:

Note: When When this button is clicked, the form is submitted to the specified page. This button can have a name attribute value. Generally, we provide the value of $_POST[‘submit’] on the server side to determine whether the current request comes from a form submission.

The above content introduces the content, functions and precautions contained in the form. Now we will learn the specific content of the form in detail.

The $_GET and $_POST variables in PHP are used to retrieve information from a form, such as user input.

PHP Form Processing

One very important thing to note is that when processing HTML forms, PHP can automatically turn form elements from the HTML page into For use by PHP scripts.

Example

The following example contains an HTML form with two input boxes and a submit button.

form.html file code is as follows:

    
   名字:  年龄: