Can I apply the required attribute to <select> fields in HTML5?
Mandatory: Have the first value empty - required works on empty values
Prerequisites: correct html5 DOCTYPE and a named input field
<select name="somename" required>
<option value="">Please select</option>
<option value="one">One</option>
</select>
As per the documentation (the listing and bold is mine)
The required attribute is a boolean attribute.
When specified, the user will be required to select a value before submitting the form.If a select element
- has a required attribute specified,
- does not have a multiple attribute specified,
- and has a display size of 1 (do not have SIZE=2 or more - omit it if not needed);
- and if the value of the first option element in the select element's list of options (if any) is the empty string (i.e. present as
value=""
),- and that option element's parent node is the select element (and not an optgroup element),
then that option is the select element's placeholder label option.
Yes, it's working:
<select name="somename" required>
<option value="">Please select</option>
<option value="one">One</option>
</select>
you have to keep first option blank.
The <select>
element does support the required
attribute, as per the spec:
- http://dev.w3.org/html5/spec-author-view/the-select-element.html#the-select-element
Which browser doesn’t honour this?
(Of course, you have to validate on the server anyway, as you can’t guarantee that users will have JavaScript enabled.)
You can use the selected
attribute for the option element to select a choice by default. You can use the required
attribute for the select element to ensure that the user selects something.
In Javascript, you can check the selectedIndex
property to get the index of the selected option, or you can check the value
property to get the value of the selected option.
According to the HTML5 spec, selectedIndex
"returns the index of the first selected item, if any, or −1 if there is no selected item. And value
"returns the value of the first selected item, if any, or the empty string if there is no selected item." So if selectedIndex = -1, then you know they haven't selected anything.
<button type="button" onclick="displaySelection()">What did I pick?</button>
<script>
function displaySelection()
{
var mySelect = document.getElementById("someSelectElement");
var mySelection = mySelect.selectedIndex;
alert(mySelection);
}
</script>