Comments on: Using Prototype Javascript to get the value of a radio group

By: amiuhle

amiuhle — Sat, 03 May 2008 09:43:09 +0000

I edited it a little so you can also set the value of the group:

(I also removed the second attribute, I just give the first radio in the group an ID, and that’s how i reference them)

function $RG(id) {
id = $(id);
var ret = new Object();

var groupName = id.name;
var form = id.form;

ret.radios = form.getInputs(’radio’, groupName);

ret.getValue = function() {
var elt = this.radios.find(function(re) {return re.checked;});
return elt ? $F(elt) : null;
};

ret.setValue = function(value) {
var elt = this.radios.find(function(re) {return re.value == value});
if(elt) elt.checked = true;
}

return ret;
}

By: Jun Wan

Jun Wan — Tue, 29 Apr 2008 15:13:41 +0000

using prototype js
if you have a group of radio button with a name says “color”, the following will return the checked value of this group

$$(’input:checked[type="radio"][name="color"]‘).pluck(’value’)

By: Jun Wan

Jun Wan — Tue, 29 Apr 2008 05:18:54 +0000

Hi Aaron, thanks for the great tips, could you please tell me how to get the selected value of each group of the radio button then?

By: Aaron D. Campbell

Aaron D. Campbell — Sun, 20 Apr 2008 14:37:38 +0000

Well, this post was about using prototype, I’ll show you how quickly you can do this in prototype. To get all the input elements whose type is radio:
$$('input[type="radio"]‘);
If you want the names and not the actual elements, you can do this:
$$('input[type="radio"]‘).pluck(’name’);
If you want only unique names (so each group rather than each element):
$$('input[type="radio"]‘).pluck(’name’).uniq();

By: Shawn S.

Shawn S. — Sun, 20 Apr 2008 03:51:40 +0000

I have been getting an error stating getElementById() is an invalid method or propertie of this object/element when trying to retrieve a single input element of type RADIO with its ID…

I am attempting to create an array of all radio box groups in a form by there name. WITHOUT having a name or ID..

I am itterating throught all elements in form. If there type == radio I assign curEl.getAttribute(”name”) to myArray[curPos]

see below
function validate(theForm) { var errorCount = 0; var allErrors = "";


// THIS ARRAY WILL BE USED FOR GROUPS OF RADIO ELEMENTS FROM FORM

//CATAGORIZED BY NAME

var radioGroups = new Array();

//var radioGroups2 = new Array();
for (i=0; i
{

    var curInput = theForm.elements[i];

//##########################################

// GROUP RADIO ELEMENTS FOR LATER PROCESSING               #

//                                                                                         #

//              WHAT I AM TRYING TO DO                                    #

// CHECK ALL RADIO BOXES, WITHOUT FIRST KNOWING THE  #

// NAME OF THE RADIO BOX.. MODULARIZING THE CODE TO   #

// WORK WITH ANY FORM                                                      #

//#########################################

if (curInput.type ==”radio”)

{

//#######################################

// INITIAL READ AND ARRAY ASSIGNMENT/INSTANTIATION #

//######################################

   if (radioGroups.length == 0)

   {

      radioGroups[0] = curInput.getAttribute(”name”);

   }

//########################################

// ARRAYS HAVE BEAN INSTANTIATED, ADD PROCEEDING    #

// GROUP NAMES FOR LATER                                              #

//                   PROCESSING                                             #

//######################################

   else

   {

      var found = “false”;

      for (i=0; i
      {

         if (radioGroups[i]== curInput.getAttribute(”name”))

         {

            found = “true”;

            i = radioGroups.length;

         }

      }

      if (found == “false”)

      {

         radioGroups[radioGroups.length] = curInput.getAttribute(”name”);

      }

} } }
this holds up processing times out, and I can’t see why it would be a never ending loop..

Is there a problem with using radioGroups.length to reset the radio groups array? I am going to try and use a holding object for radioGroups.length see if that dose the trick.

By: Richard Hart

Richard Hart — Mon, 14 Apr 2008 21:11:38 +0000

Great! Thanks for sharing.

By: vrann

vrann — Mon, 17 Mar 2008 09:32:32 +0000

I use it)

By: Andres

Andres — Sun, 16 Mar 2008 23:58:42 +0000

Great function. i think it should be included in the next version of prototype

By: Aaron D. Campbell

Aaron D. Campbell — Wed, 24 Oct 2007 14:42:12 +0000

Sorry, I was on vacation. Here are solutions similar to yours:

$$("input[type=radio][name='radioGroupName'][value='yourDefaultValue']“).writeAttribute(”checked”, “checked”); $(”someRadioGroupMember”).writeAttribute(”checked”, “checked”);

By: Ville Walveranta

Ville Walveranta — Sun, 21 Oct 2007 04:21:57 +0000

But how to *set* radio group value and selected button in prototype?

In other words, I’m looking for the prototype equivalent for jQuery’s…
$("#some_radio_group").val("myDefaultValue"); $("#some_radio_group_member1").attr("checked", "checked");

Probably (?) easy; I just started using prototype two days ago, and haven’t figured this one out yet :). Thanks for any insights.