HTML Forms

An HTML form is used to collect user input. The user input is most often sent to a server for processing.

Example

The form Element

The HTML <form> element is used to create an HTML form for user input:


                        <form> 

                        .

                        form elements

                        .

                        <form>

The <form> element is a container for different types of input elements, such as: text fields, checkboxes, radio buttons, submit buttons, etc.

The input Element

The HTML <input> element is the most used form element.

An <input> element can be displayed in many ways, depending on the type attribute.

Here are some examples:

Type	Description
<input type="text">	Displays a single-line text input field
<input type="radio">	Displays a radio button (for selecting one of many choices)
<input type="checkbox">	Displays a checkbox (for selecting zero or more of many choices)
<input type="submit">	Displays a submit button (for submitting the form)
<input type="button">	Displays a clickable button

Text Fields

The <input type="text"> defines a single-line input field for text input.

Example

A form with input fields for text:


                                <form>
                                <label for="fname">First name:</label>

                                <input type="text" id="fname" name="fname">

                                <label for="lname">Last name:</label>

                                <input type="text" id="lname" name="lname">
                                </form>

This is how the HTML code above will be displayed in a browser:

Note: The form itself is not visible. Also note that the default width of an input field is 20 characters.

The label Element

Notice the use of the <label> element in the example above.

The <label> tag defines a label for many form elements.

The <label> element is useful for screen-reader users, because the screen-reader will read out loud the label when the user focuses on the input element.

The <label> element also helps users who have difficulty clicking on very small regions (such as radio buttons or checkboxes) - because when the user clicks the text within the <label> element, it toggles the radio button/checkbox.

The <label> attribute of the <label> tag should be equal to the id attribute of the <input> element to bind them together.

Radio Buttons

The <input type="radio"> defines a radio button.

Radio buttons let a user select ONE of a limited number of choices.

Example

A form with radio buttons:


                                <p>Choose your favorite Web language:</p>

                                

                                <form>

                                <input type="radio" id="html" name="fav_language" value="HTML">

                                <label for="html">HTML</label<br>

                                <input type="radio" id="css" name="fav_language" value="CSS">

                                <label for="css">CSS</label><br>

                                <input type="radio" id="javascript" name="fav_language" value="JavaScript">

                                <label for="javascript">JavaScript</label>

                                </form>

This is how the HTML code above will be displayed in a browser:

Choose your favorite Web language:

Checkboxes

The <input type="checkbox"> defines a checkbox.

Checkboxes let a user select ZERO or MORE options of a limited number of choices.

Example

A form with checkboxes:


                                <form>

                                    <input type="checkbox" id="vehicle1" name="vehicle1" value="Bike">

                                    <label for="vehicle1"> I have a bike </label> <br>

                                    <input type="checkbox" id="vehicle2" name="vehicle2" value="Car">

                                    <label for="vehicle2"> I have a car </label> <br>

                                    <input type="checkbox" id="vehicle3" name="vehicle3" value="Boat">

                                    <label for="vehicle3"> I have a boat </label>

                                </form>

This is how the HTML code above will be displayed in a browser:

The Submit Button

The <input type="submit"> defines a button for submitting the form data to a form-handler.

The form-handler is typically a file on the server with a script for processing input data.

The form-handler is specified in the form's action attribute.

Example

A form with a submit button:


                                <form action="/action_page.php">

                                  <label for="fname">First name:</label><br>

                                  <input type="text" id="fname" name="fname" value="John"><br>

                                  <label for="lname">Last name:</label><br>

                                  <input type="text" id="lname" name="lname" value="Doe"><br><br>

                                  <input type="submit" value="Submit">

                                </form>

This is how the HTML code above will be displayed in a browser:

The Name Attribute for input

Notice that each input field must have a name attribute to be submitted.

If the name attribute is omitted, the value of the input field will not be sent at all.

Example

This example will not submit the value of the "First name" input field:


                                <form action="/action_page.php">

                                  <label for="fname">First name:</label><br>

                                  <input type="text" id="fname" value="John"><br><br>

                                  <input type="submit" value="Submit">

                                </form>

HTML Form Attributes

This chapter describes the different attributes for the HTML <form> element.

The Action Attribute

The action attribute defines the action to be performed when the form is submitted.

Usually, the form data is sent to a file on the server when the user clicks on the submit button.

In the example below, the form data is sent to a file called "action_page.php". This file contains a server-side script that handles the form data:

Example

On submit, send form data to "action_page.php":


                                <form action="/action_page.php">

                                <label for="fname">First name:</label><br>

                                <input type="text" id="fname" name="fname" value="John"><br>

                                <label for="lname">Last name:</label><br>

                                <input type="text" id="lname" name="lname" value="Doe"><br><br>

                                <input type="submit" value="Submit">

                                </form>

Tip: If the action attribute is omitted, the action is set to the current page.

The Target Attribute

The target attribute specifies where to display the response that is received after submitting the form.

The target attribute can have one of the following values:

Value	Description
_blank	The response is displayed in a new window or tab
_self	The response is displayed in the current window
_parent	The response is displayed in the parent frame
_top	The response is displayed in the full body of the window
framename	The response is displayed in a named iframe

The default value is _self which means that the response will open in the current window.

Example

Here, the submitted result will open in a new browser tab:


                                <form action="/action_page.php" target="_blank">

The Method Attribute

The method attribute specifies the HTTP method to be used when submitting the form data.

The form-data can be sent as URL variables (with method="get") or as HTTP post transaction (with method="post").

The default HTTP method when submitting form data is GET.

Example

This example uses the GET method when submitting the form data:


                                <form action="/action_page.php" method="get">

Example

This example uses the POST method when submitting the form data:


                                <form action="/action_page.php" method="post">

Notes on GET:

Appends the form data to the URL, in name/value pairs
NEVER use GET to send sensitive data! (the submitted form data is visible in the URL!)
The length of a URL is limited (2048 characters)
Useful for form submissions where a user wants to bookmark the result
GET is good for non-secure data, like query strings in Google

Notes on POST:

Appends the form data inside the body of the HTTP request (the submitted form data is not shown in the URL)
POST has no size limitations, and can be used to send large amounts of data.
Form submissions with POST cannot be bookmarked

Tip: Always use POST if the form data contains sensitive or personal information!

The Autocomplete Attribute

The autocomplete attribute specifies whether a form should have autocomplete on or off.

When autocomplete is on, the browser automatically complete values based on values that the user has entered before.

Example

A form with autocomplete on:


                                <form action="/action_page.php" autocomplete="on">

The Novalidate Attribute

The novalidate attribute is a boolean attribute.

When present, it specifies that the form-data (input) should not be validated when submitted.

Example


                                <form action="/action_page.php" novalidate>