HTML Form Elements

HTML Form Elements

HTML form on a web page allows a user to enter data that is sent to a server for processing. Forms can resemble paper or database forms because web users fill out the forms using checkboxes, radio buttons, or text fields.

For example, forms can be used to enter shipping or credit card data to order a product, or can be used to retrieve search results from a search engine.

This chapter describes all HTML form elements.

The <input> Element

The most important form element is the <input> element.

The <input> element can vary in many ways, depending on the type attribute.

The <select> Element (Drop-Down List)

The <select> element defines a drop-down list:

The <option> elements defines the options to select.

The list will normally show the first item as selected.

You can add a selected attribute to define a predefined option.

The <textarea> Element

The <textarea> element defines a multi-line input field (a text area):

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

The cat was playing in the garden.

The <button> Element

The <button> element defines a clickable button:

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

Click Me!

HTML5 Form Elements

HTML5 added the following form elements:

• <datalist>
• <keygen>
• <output>

HTML5 <datalist> Element

The <datalist> element specifies a list of pre-defined options for an <input> element.

Users will see a drop-down list of pre-defined options as they input data.

The list attribute of the <input> element, must refer to the id attribute of the <datalist> element.

Example

An <input> element with pre-defined values in a <datalist>:

<form action="action_page.php">
  <input list="browsers">
  <datalist id="browsers">
    <option value="Internet Explorer">
    <option value="Firefox">
    <option value="Chrome">
    <option value="Opera">
    <option value="Safari">
  </datalist>
</form>

Try it Yourself »

HTML5 <keygen> Element

The purpose of the <keygen> element is to provide a secure way to authenticate users.

The <keygen> element specifies a key-pair generator field in a form.

When the form is submitted, two keys are generated, one private and one public.

The private key is stored locally, and the public key is sent to the server.

The public key could be used to generate a client certificate to authenticate the user in the future.

Example

A form with a keygen field:

<form action="action_page.php">
  Username: <input type="text" name="user">
  Encryption: <keygen name="security">
  <input type="submit">
</form>

Try it Yourself »

HTML5 <output> Element

The <output> element represents the result of a calculation (like one performed by a script).

Example

Perform a calculation and show the result in an <output> element:

<form action="action_page.asp"
  oninput="x.value=parseInt(a.value)+parseInt(b.value)">
  0
  <input type="range"  id="a" name="a" value="50">
  100 +
  <input type="number" id="b" name="b" value="50">
  =
  <output name="x" for="a b"></output>
  <br><br>
  <input type="submit">
</form>

Try it Yourself »

Test Yourself with Exercises!

Exercise 1 »   Exercise 2 »   Exercise 3 »

HTML Form Elements

= new in HTML5.