We now look at the functionality of non-
<input> form elements in detail, from other control types such as drop-down lists and multi-line text fields, to other useful form features such as the
<output> element (which we saw in action in the previous article), and progress bars.
|Prerequisites:||Basic computer literacy, and a basic understanding of HTML.|
|Objective:||To understand the non-
Multi-line text fields
<textarea cols="30" rows="8"></textarea>
This renders like so:
The main difference between a
<textarea> and a regular single line text field is that users are allowed to include hard line breaks (i.e. pressing return) that will be included when the data is submitted.
<textarea> also takes a closing tag, and any default text you want it to contain should be put between the opening and closing tags. In contrast, the
<input> is an empty element with no closing tag — any default value is put inside the
Note that even though you can put anything inside a
contenteditable on non-form controls provides an API for capturing HTML/"rich" content instead of plain text).
Visually, the text entered wraps and the form control is by default resizable. Modern browsers provide a drag handle that you can drag to increase/decrease the size of the text area.
The following screenshots show default, focused, and disabled
<textarea> elements in Firefox 71 and Safari 13 on macOS, and Edge 18, Yandex 14, Firefox 71 and Chrome 79 on Windows 10.
Controlling multi-line rendering
<textarea> accepts three attributes to control its rendering across several lines:
- Specifies the visible width (columns) of the text control, measured in average character widths. This is effectively the starting width, as it can be changed by resizing the
<textarea>, and overriden using CSS. The default value if none is specified is 20.
- Specifies the number of visible text rows for the control. This is effectively the starting height, as it can be changed by resizing the
<textarea>, and overriden using CSS. The default value if none is specified is 2.
- Specifies how the control wraps text. The default value is
soft, which means that the words wrap after whole words. Other values are
hard, which seems to behave in a similar manner to
off, which stops it from wrapping.
Controlling textarea resizability
The ability to resize a
<textarea> is controlled with the CSS
resize property. Its possible values are:
both: The default — allows resizing horizontally and vertically.
horizontal: Allows resizing only horizontally.
vertical: Allows resizing only vertically.
none: Allows no resizing.
inline: Experimental values that allow resizing in the
inlinedirection only (this varies depending on the directionality of your text; read Handling different text directions if you want to find out more.)
Play with the interactive example at the top of the
resize reference page for a demonstration of how these work.
Drop-down controls are a simple way to let users select from many different options without taking up much space in the user interface. HTML has two forms of drop down content: the select box, and the autocomplete box. In both cases the interaction is the same — once the control is activated, the browser displays a list of values the user can select between.
<select id="simple" name="simple"> <option>Banana</option> <option selected>Cherry</option> <option>Lemon</option> </select>
<select id="groups" name="groups"> <optgroup label="fruits"> <option>Banana</option> <option selected>Cherry</option> <option>Lemon</option> </optgroup> <optgroup label="vegetables"> <option>Carrot</option> <option>Eggplant</option> <option>Potato</option> </optgroup> </select>
<optgroup> element, the value of the
label attribute is displayed before the values of the nested options. The browser usually sets them visually apart from the options (i.e. by being bolded and at a different nesting level) so they are less likely to be confused for actual options.
<option> element has an explicit
value attribute set on it, that value is sent when the form is submitted with that option selected. If the
value attribute is omitted, as with the examples above, the content of the
<option> element is used as the value. So
value attributes are not needed, but you might find a reason to want to send a shortened or different value to the server than what is visually shown in the select box.
<select id="simple" name="simple"> <option value="banana">Big, beautiful yellow banana</option> <option value="cherry">Succulent, juicy cherry</option> <option value="lemon">Sharp, powerful lemon</option> </select>
By default, the height of the select box is enough to display a single value. The optional
size attribute provides control over how many options are visible when the select does not have focus.
Multiple choice select box
By default, a select box only lets the user select a single value. By adding the
multiple attribute to the
<select> element, you can allow users to select several values, by using the default mechanism provided by the operating system (e.g. holding down Cmd/Ctrl and clicking multiple values on desktop).
<select id="multi" name="multi" multiple size="2"> <optgroup label="fruits"> <option>Banana</option> <option selected>Cherry</option> <option>Lemon</option> </optgroup> <optgroup label="vegetables"> <option>Carrot</option> <option>Eggplant</option> <option>Potato</option> </optgroup> </select>
Note: In the case of multiple choice select boxes, you'll notice that the select box no longer displays the values as drop-down content — instead, all values are displayed at once in a list, with the optional
size attribute determining the height of the widget.
You can provide suggested, automatically-completed values for form widgets using the
<datalist> element with child
<option> elements to specify the values to display. The
<datalist> needs to be given an
Once a data list is affiliated with a form widget, its options are used to auto-complete text entered by the user; typically, this is presented to the user as a drop-down box listing possible matches for what they've typed into the input.
Let's look at an example.
<label for="myFruit">What's your favorite fruit?</label> <input type="text" name="myFruit" id="myFruit" list="mySuggestion"> <datalist id="mySuggestion"> <option>Apple</option> <option>Banana</option> <option>Blackberry</option> <option>Blueberry</option> <option>Lemon</option> <option>Lychee</option> <option>Peach</option> <option>Pear</option> </datalist>
Datalist support and fallbacks
Almost all browsers support datalist, but if you are still supporting older browsers such as IE versions below 10, there is a trick to provide a fallback:
<label for="myFruit">What is your favorite fruit? (With fallback)</label> <input type="text" id="myFruit" name="fruit" list="fruitList"> <datalist id="fruitList"> <label for="suggestion">or pick a fruit</label> <select id="suggestion" name="altFruit"> <option>Apple</option> <option>Banana</option> <option>Blackberry</option> <option>Blueberry</option> <option>Lemon</option> <option>Lychee</option> <option>Peach</option> <option>Pear</option> </select> </datalist>
Browsers that support the
<datalist> element will ignore all the elements that are not
<option> elements, with the datalist working as expected. Old browsers that don't support the
<datalist> element will display the label and the select box.
The following screenshot shows the datalist fallback as rendered in Safari 6:
If you use this fallback, ensure the data for both the
<input> and the
<select> are collected server-side.
Less obvious datalist uses
According to the HTML specification, the
list attribute and the
<datalist> element can be used with any kind of widget requiring a user input. This leads to some uses of it that might seem a little non-obvious.
For example, in browsers that support
range input types, a small tick mark will be displayed above the range for each datalist
value. You can see an implementation example of this on the
<input type="range"> reference page.
In this case, different browsers behave differently from case to case, so consider such uses as progressive enhancement, and ensure they degrade gracefully.
Other form features
There are a few other form features that are not as obvious as the ones we have already mentioned, but still useful in some situations, so we thought it would be worth giving them a brief mention.
Meters and progress bars
Meters and progress bars are visual representations of numeric values.
<progress max="100" value="75">75/100</progress>
This is for implementing anything requiring progress reporting, such as the percentage of total files downloaded, or the number of questions filled in on a questionnaire.
The content inside the
<progress> element is a fallback for browsers that don't support the element and for screen readers to vocalize it.
A meter bar represents a fixed value in a range delimited by a
min values. This value is visualy rendered as a bar, and to know how this bar looks, we compare the value to some other set values:
highvalues divide the range in three parts:
optimumvalue defines the optimum value for the
<meter>element. In conjuction with the
highvalue, it defines which part of the range is prefered:
- If the
optimumvalue is in the lower part of the range, the lower range is considered to be the prefered part, the medium range is considered to be the average part, and the higher range is considered to be the worst part.
- If the
optimumvalue is in the medium part of the range, the lower range is considered to be an average part, the medium range is considered to be the prefered part, and the higher range is considered to be average as well.
- If the
optimumvalue is in the higher part of the range, the lower range is considered to be the worst part, the medium range is considered to be the average part and the higher range is considered to be the prefered part.
- If the
All browsers that implement the
<meter> element use those values to change the color of the meter bar:
- If the current value is in the prefered part of the range, the bar is green.
- If the current value is in the average part of the range, the bar is yellow.
- If the current value is in the worst part of the range, the bar is red.
Such a bar is created using a
<meter> element. This is for implementing any kind of meter, for example a bar showing total space used on a disk, which turns red when it starts to get full.
<meter min="0" max="100" value="75" low="33" high="66" optimum="50">75</meter>
The content inside the
<meter> element is a fallback for browsers that don't support the element and for assistive technologies to vocalize it.
As you'll have seen in the last few articles, there are a lot of different types of available form element. You don't need to remember all of these details at once, and can return to these articles as often as you like to check up on details.
Now that you have a grasp of the HTML behind the different available form controls, we'll take a look at Styling them.
In this module
- Your first form
- How to structure a web form
- Basic native form controls
- The HTML5 input types
- Other form controls
- Styling web forms
- Advanced form styling
- UI pseudo-classes
- Client-side form validation
- Sending form data