HTML form

Element

Element determine user input data collection form.

 . 
 các phần tử của form 
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The form in HTML contains form elements - the element types that take input data such as filling in text fields, checkboxes, buttons, submit buttons .

Element

This is the most important element of the form, can be displayed in many ways, depending on the type of attribute. Here are some examples.

1. type = 'text'> Define a text entry line
2. type = 'radio'> Define a round button to select one of the answers
3. type = 'submit'> Button definition to submit / submit forms

Input data is text

Define a text entry line:

  Tên: 
 
 
 
  Họ: 
 
 

HTML form Picture 1
Enter the input data in writing

Note: The form itself does not appear and the field's default width is 20 characters.

Round button to select input data

type = 'radio'> defines a round button for users to select one of the answers.

  Nam 
 
  Nữ 
 
  Khác 
 

HTML form Picture 2
Round button to select 1 of the available answers

Submit form / submit form

type = 'submit'> button definition to submit / submit the form to the form-handler, usually the home page that has the script to handle the input data. Form-handler is specified in the action attribute of the form.

  Tên: 
 
 
 
  Họ: 
 
 
 
 
 

HTML form Picture 3
Images displayed on the browser

Action attribute

The action attribute defines what happens when the form is submitted. Normally, data will be sent to the website on the server when the user clicks on the submit button. In the above example, the data is sent to the '/action_page.php' page . The page containing the server's script will process the data sent.

If the action attribute is omitted, the form will be sent to the current page.

Target attribute

The target attribute determines whether the sent result will be displayed on the browser's new tab, in the frame or in the current window. The default value is '_self ', which means that the submitted form opens in the current window.

To display results on another tab, use the value '_blank'

Other values ​​can be used as '_parent' and '_top' or a name that represents the name of the iframe.

Method properties

The method attribute specifies the HTTP method (GET or POST) to be used when submitting data in the form.

or

When to use GET?

The default method when submitting form data is GET but when using GET, the data in the form will be visible on the address of the page:

 /action_page.php?firstname=Mickey&lastname=Mouse 

Note about GET

1. The data in the form will be added behind the URL in name / value pairs.
2. URL length is limited (about 300 characters).
3. Do not use GET to send sensitive data (visible in the URL).
4. Useful when users want to bookmark results.
5. Recommended for non-confidential data, such as query strings in Google.

When to use POST?

Remember to always use POST when the data in the form contains personal, important, sensitive information. POST does not display data on the page address.

Note about POST

1. POST is not limited to size, can be used to send large amounts of data.
2. The POST form page cannot be bookmarked.

Name attribute

Each input field must have a name. attribute name. If ignored, that data will not be sent. The example below will only send to 'LastName' because the 'Name' input element has no n a me attribute.

  First name: 
 
 
 
  Last name: 
 
 
 
 
 

Group data in the form by

Element

used to group related data in the form. Element Describe the description for the element

  Thông tin cá nhân: 
  Tên: 
 
 
 
  Họ: 
 
 
 
 
  
 

HTML form Picture 4
Group related data by element

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