Form elements and attributes in HTML5 provide a greater degree of semantic mark-up than HTML4 and remove a great deal of the need for tedious scripting and styling that was required in HTML4. The forms features in HTML5 provide a better experience for users by making forms more consistent across different web sites and giving immediate feedback to the user about data entry. They also provide this experience to users who have scripting disabled in their browser.
This article summarizes changes to HTML forms introduced in HTML5. For a detailed guide to using forms, see our extensive HTML forms guide.
The <input>
element
The
element has new values for the <input>
type
attribute. (See the <input>
reference page for a complete list of attributes, values, and usages for this element.)
search
: The element represents search entry field. Line breaks are automatically stripped from the input value, but no other syntax is enforced.tel
: The element represents a control for editing a telephone number. Line breaks are automatically stripped from the input value, but no other syntax is enforced, because telephone numbers vary widely internationally. You can use attributes such aspattern
andmaxlength
to restrict values entered in the control.url
: The element represents a control for editing a URL. Line breaks and leading and trailing whitespaces are automatically stripped from the input value.-
email
: The element represents one email address. Line breaks are automatically stripped from the input value. An invalid email address can be set, but the input field will only satisfy its constraints if the email address satisfies the ABNF production1*( atext / "." ) "@" ldh-str 1*( "." ldh-str )
whereatext
is defined in RFC 5322 section 3.2.3, andldh-str
is defined in RFC 1034 section 3.5.
The <input>
element also has new attributes:
list
: The ID of a<datalist>
element whose content,<option>
elements, are to be used as hints and are displayed as proposals in the suggestion area of the input field.pattern
: A regular expression that the control's value is checked against, which can be used withtype
values oftext
,tel
,search
,url
, andemail
.form
: A string indicating which<form>
element this input is part of. An input can only be in one form.formmethod
: A string indicating which HTTP method (GET or POST) should be used when submitting; it overrides themethod
of the<form>
element, if defined. Theformmethod
only applies when thetype
isimage
orsubmit, and the
form
attribute has been set.x-moz-errormessage
: A string that is displayed as an error message when the field fails to validate. This is a Mozilla extension, and is non-standard.
text input
This segment defines a one line input the user can enter into the box.
<form> Enter your Name <input type="text" name="name"> </form>
checkboxes
This section allows the user to select multiple options to choose from a limited numbers of options.
<input type="checkbox" name="chk" value="" checked> Do you want the newsletter
Radio < input> element
<form>
<input type="radio" name="sex" value="male">Male<br>
<input type="radio" name="sex" value="female">Female<br>
<input type="radio" name="sex" value="other">Other
</form>
The <form>
element
The <form>
element has a new attribute:
novalidate
: This attribute prevents the form from being validated before its submission.
The <datalist>
element
The <datalist>
element represents the list of <option>
elements to suggest when filling an <input>
field.
You can use the list
attribute on an <input>
element to link a specific input field with a specific <datalist>
element.
The <output>
element
The
element represents the result of a calculation.<output>
You can use the for
attribute to specify a relationship between the
element and other elements in the document that affected the calculation (for example, as inputs or parameters). The value of the <output>
for
attribute is a space-separated list of IDs of other elements.
Gecko 2.0 (but not necessarily other browser engines) supports defining custom validity constraints and error messages for <output>
elements, and therefore applies the :invalid
, :valid
, :-moz-ui-invalid
, and :-moz-ui-valid
CSS pseudo-classes to them. This can be helpful in situations where the calculated result violates a business rule, but no specific input value does (for example, "The total of percentages must not exceed 100").
The placeholder attribute
The placeholder
attribute on
and <input>
elements provides a hint to the user of what can be entered in the field. The placeholder text must not contain carriage returns or line-feeds.<textarea>
The autofocus attribute
The autofocus
attribute lets you specify that a form control should have input focus when the page loads, unless the user overrides it, for example by typing in a different control. Only one form item in a document can have the autofocus
attribute, which is a Boolean. This attribute can be applied to the
, <input>
, <button>
, and <select>
elements. The exception is that <textarea>
autofocus
cannot be applied to an autofocus
element if the type
attribute is set to hidden
(that is, you cannot automatically set focus to a hidden control).
The label.control DOM property
The HTMLLabelElement
DOM interface provides an extra property, in addition to the properties that correspond to the HTML
element attributes. The control property returns the labeled control, that is, the control that the label is for, which is determined by the <label>
for
attribute (if it is defined) or by the first descendant control element.
Constraint Validation
HTML5 provides syntax and API items to support client-side validation of forms. While this functionality does not replace server-side validation, which is still necessary for security and data integrity, client-side validation can support a better user experience by giving the user immediate feedback about the input data.
If the title
attribute is set on the <input>
element, its value is used as tooltip. However, if the validation fails, this tooltip text will be replaced with the associated error message. It is possible to customize this error message using the non-standard x-moz-errormessage
attribute or when calling the setCustomValidity()
method.
<input type="email" title="Please, provide an e-mail" x-moz-errormessage="This is not a valid e-mail">
<button>
elements in a form; to style a button based on the validity of the associated form, use the :-moz-submit-invalid
pseudo-class.HTML Syntax for Constraint Validation
The following items in HTML5 syntax can be used to specify constraints on form data.
- The
required
attribute on the<input>
,<select>
, and<textarea>
elements indicates that a value must be supplied. (On the<input>
element,required
applies only in conjunction with certain values of thetype
attribute.) - The
pattern
attribute on the<input>
element constrains the value to match a specific regular expression. - The
min
andmax
attributes of the<input>
element constrain the minimum and maximum values that can be entered. - The
step
attribute of the<input>
element (when used in combination with themin
andmax
attributes) constrains the granularity of values that can be entered. A value that does not correspond an allowed value step does not validate. - The
maxlength
attribute of the<input>
and<textarea>
elements constrains the maximum number of characters (in Unicode code points) that the user can enter. - The values
url
andemail
for thetype
constrain the value to being a valid URL or e-mail address, respectively.
In addition, you can prevent constraint validation by specifying the novalidate
attribute on the <form>
, or the formnovalidate
attribute on the <button>
element and on the <input>
element (when type
is submit
or image
). These attributes indicate that the form is not to be validated when it is submitted.
Constraint Validation API
The following DOM properties and methods related to constraint validation are available to client-side scripts:
- On
HTMLFormElement
objects, thecheckValidity()
method, which returns true if all of this form element's associated elements that are subject to constraint validation satisfy their constraints, and false if any do not. - On form-associated elements:
willValidate
property, which is false if the element has constraints that are not satisfied.validity
property, which is aValidityState
object representing the validity states that the element is in (i.e., constraint failure or success conditions).validationMessage
property, which is a message describing any constraint failures that pertain to the element.checkValidity()
method, which returns false if the element fails to satisfy any of its constraints, or true otherwise.setCustomValidity()
method, which sets a custom validation message, allowing for constraints to be imposed and validated beyond those that are predefined.