RadioNodeList polyfill

polyfill.js

/*
  demo :- http://jsfiddle.net/bjkkD/20/

  Implements RadioNodeList :- http://www.whatwg.org/specs/web-apps/current-work/multipage/common-dom-interfaces.html#radionodelist

  Implementation just adds `.value` as a property to `NodeList`.

  Requires ES5 shim and ES5 shimmable browser. (Modern and IE8)
*/
;(function () {
    Object.defineProperty(NodeList.prototype, "value", {
        get: getRadioNodeListValue,
        set: setRadioNodeListValue,
        configurable: true            
    });
       
    function getRadioNodeListValue() {
        for (var i = 0, len = this.length; i < len; i++) {
            var el = this[i];
            if (el.checked) {
                return el.value;   
            }
        }
    }
    
    function setRadioNodeListValue(value) {
        for (var i = 0, len = this.length; i < len; i++) {
            var el = this[i];
            if (el.checked) {
                el.value = value;
                return;   
            }
        }    
    }
}());

For IE11 I had to change this to define the property on HTMLCollection instead of NodeList, since myform.elements.myradiosetname returns an HTMLCollection rather than a NodeList.

Any comments on that? When would you have a NodeList instead?

I also wrapped it in a conditional: if (typeof RadioNodeList === "undefined") { so it doesn't run where browsers support RadioNodeList.