Why can't radio buttons be “readonly”?

Question

I would like to show a radio button, have its value submitted, but depending on the circumstances, have it not editable. Disabled doesn't work, because it doesn't submit the value (or does it?), and it grays out the radio button. Read-only is really what I'm looking for, but for some mysterious reason it doesn't work.

Is there some weird trick I need to pull to get read-only to work as expected? Should I just do it in JavaScript instead?

Incidentally, does anyone know why read-only doesn't work in radio buttons, while it does work in other input tags? Is this one of those incomprehensible omissions in the HTML specs?

Answer 1

I've faked readonly on a radio button by disabling only the un-checked radio buttons. It keeps the user from selecting a different value, and the checked value will always post on submit.

Using jQuery to make readonly:

$(':radio:not(:checked)').attr('disabled', true);

This approach also worked for making a select list readonly, except that you'll need to disable each un-selected option.

Answer 2

Radio buttons would only need to be read-only if there are other options. If you don't have any other options, a checked radio button cannot be unchecked. If you have other options, you can prevent the user from changing the value merely by disabling the other options:

<input type="radio" name="foo" value="Y" checked>
<input type="radio" name="foo" value="N" disabled>

Fiddle: http://jsfiddle.net/qqVGu/

Answer 3

This is the trick you can go with.

<input type="radio" name="name" onclick="this.checked = false;" />

Answer 4

I have a lengthy form (250+ fields) that posts to a db. It is an online employment application. When an admin goes to look at an application that has been filed, the form is populated with data from the db. Input texts and textareas are replaced with the text they submitted but the radios and checkboxes are useful to keep as form elements. Disabling them makes them harder to read. Setting the .checked property to false onclick won't work because they may have been checked by the user filling out the app. Anyhow...

onclick="return false;"

works like a charm for 'disabling' radios and checkboxes ipso facto.

Answer 5

The best solution is to set the checked or unchecked state (either from client or server) and to not let the user change it after wards (i.e make it readonly) do the following:

<input type="radio" name="name" onclick="javascript: return false;" />

Answer 6

I've come up with a javascript-heavy way to achieve a readonly state for check boxes and radio buttons. It is tested against current versions of Firefox, Opera, Safari, Google Chrome, as well as current and previous versions of IE (down to IE7).

Why not simply use the disabled property you ask? When printing the page, disabled input elements come out in a gray color. The customer for which this was implemented wanted all elements to come out the same color.

I'm not sure if I'm allowed to post the source code here, as I developed this while working for a company, but I can surely share the concepts.

With onmousedown events, you can read the selection state before the click action changes it. So you store this information and then restore these states with an onclick event.

<input id="r1" type="radio" name="group1" value="r1" onmousedown="storeSelectedRadiosForThisGroup(this.name);" onclick="setSelectedStateForEachElementOfThisGroup(this.name);" checked="checked">Option 1</input>
<input id="r2" type="radio" name="group1" value="r2" onmousedown="storeSelectedRadiosForThisGroup(this.name);" onclick="setSelectedStateForEachElementOfThisGroup(this.name);">Option 2</input>
<input id="r3" type="radio" name="group1" value="r3" onmousedown="storeSelectedRadiosForThisGroup(this.name);" onclick="setSelectedStateForEachElementOfThisGroup(this.name);">Option 3</input>

<input id="c1" type="checkbox" name="group2" value="c1" onmousedown="storeSelectedRadiosForThisGroup(this.name);" onclick="setSelectedStateForEachElementOfThisGroup(this.name);" checked="checked">Option 1</input>
<input id="c2" type="checkbox" name="group2" value="c2" onmousedown="storeSelectedRadiosForThisGroup(this.name);" onclick="setSelectedStateForEachElementOfThisGroup(this.name);">Option 2</input>
<input id="c3" type="checkbox" name="group2" value="c3" onmousedown="storeSelectedRadiosForThisGroup(this.name);" onclick="setSelectedStateForEachElementOfThisGroup(this.name);" checked="checked">Option 3</input>

The javascript portion of this would then work like this (again only the concepts):

var selectionStore = new Object();  // keep the currently selected items' ids in a store

function storeSelectedRadiosForThisGroup(elementName) {
    // get all the elements for this group
    var radioOrSelectGroup = document.getElementsByName(elementName);

    // iterate over the group to find the selected values and store the selected ids in the selectionStore
    // ((radioOrSelectGroup[i].checked == true) tells you that)
    // remember checkbox groups can have multiple checked items, so you you might need an array for the ids
    ...
}

function setSelectedStateForEachElementOfThisGroup(elementName) {
    // iterate over the group and set the elements checked property to true/false, depending on whether their id is in the selectionStore
    ...

    // make sure you return false here
    return false;
}

You can now enable/disable the radio buttons/checkboxes by changing the onclick and onmousedown properties of the input elements.

Answer 7

For the non-selected radio buttons, flag them as disabled. This prevents them from responding to user input and clearing out the checked radio button. For example:

<input type="radio" name="var" checked="yes" value="Yes"></input>
<input type="radio" name="var" disabled="yes" value="No"></input>

Answer 8

JavaScript way - this worked for me.

<script>
$(document).ready(function() {
   $('#YourTableId').find('*').each(function () { $(this).attr("disabled", true); });
});
</script>

Reason:

1. $('#YourTableId').find('*') -> this returns all the tags.

2. $('#YourTableId').find('*').each(function () { $(this).attr("disabled", true); }); iterates over all objects captured in this and disable input tags.

Analysis (Debugging):

1. form:radiobutton is internally considered as an "input" tag.

2. Like in the above function(), if you try printing document.write(this.tagName);

3. Wherever, in tags it finds radio buttons, it returns an input tag.

So, above code line can be more optimized for radio button tags, by replacing * with input: $('#YourTableId').find('input').each(function () { $(this).attr("disabled", true); });

Answer 9

A fairly simple option would be to create a javascript function called on the form's "onsubmit" event to enable the radiobutton back so that it's value is posted with the rest of the form.
It does not seem to be an omission on HTML specs, but a design choice (a logical one, IMHO), a radiobutton can't be readonly as a button can't be, if you don't want to use it, then disable it.

Answer 10

I found that use onclick='this.checked = false;' worked to a certain extent. A radio button that was clicked would not be selected. However, if there was a radio button that was already selected (e.g., a default value), that radio button would become unselected.

<!-- didn't completely work -->
<input type="radio" name="r1" id="r1" value="N" checked="checked" onclick='this.checked = false;'>N</input>
<input type="radio" name="r1" id="r1" value="Y" onclick='this.checked = false;'>Y</input>

For this scenario, leaving the default value alone and disabling the other radio button(s) preserves the already selected radio button and prevents it from being unselected.

<!-- preserves pre-selected value -->
<input type="radio" name="r1" id="r1" value="N" checked="checked">N</input>
<input type="radio" name="r1" id="r1" value="Y" disabled>Y</input>

This solution is not the most elegant way of preventing the default value from being changed, but it will work whether or not javascript is enabled.

Answer 11

Try the attribute disabled, but I think the you won't get the value of the radio buttons. Or set images instead like:

<img src="itischecked.gif" alt="[x]" />radio button option

Best Regards.

Answer 12

I'm using a JS plugin that styles checkbox/radio input elements and used the following jQuery to establish a 'readonly state' where the underlying value is still posted but the input element appears inaccessible to the user, which is I believe the intended reason we would use a readonly input attribute...

if ($(node).prop('readonly')) {
    $(node).parent('div').addClass('disabled'); // just styling, appears greyed out
    $(node).on('click', function (e) {
        e.preventDefault();
    });
}

Answer 13

What about capturing an "On_click()" event in JS and checking it like here?:

http://www.dynamicdrive.com/forums/showthread.php?t=33043