source: Dev/trunk/src/client/dijit/form/DataList.js

define([
        "dojo/_base/declare", // declare
        "dojo/dom", // dom.byId
        "dojo/_base/lang", // lang.trim
        "dojo/query", // query
        "dojo/store/Memory",
        "../registry"   // registry.add registry.remove
], function(declare, dom, lang, query, MemoryStore, registry){

        // module:
        //              dijit/form/DataList

        function toItem(/*DOMNode*/ option){
                // summary:
                //              Convert `<option>` node to hash
                return {
                        id: option.value,
                        value: option.value,
                        name: lang.trim(option.innerText || option.textContent || '')
                };
        }

        return declare("dijit.form.DataList", MemoryStore, {
                // summary:
                //              Inefficient but small data store specialized for inlined data via OPTION tags
                //
                // description:
                //              Provides a store for inlined data like:
                //
                //      |       <datalist>
                //      |               <option value="AL">Alabama</option>
                //      |               ...

                constructor: function(params, srcNodeRef){
                        // summary:
                        //              Create the widget.
                        // params: Object|null
                        //              Hash of initialization parameters for widget, including scalar values (like title, duration etc.)
                        //              and functions, typically callbacks like onClick.
                        //              The hash can contain any of the widget's properties, excluding read-only properties.
                        // srcNodeRef: DOMNode|String
                        //              Attach widget to this DOM node.

                        // store pointer to original DOM tree
                        this.domNode = dom.byId(srcNodeRef);

                        lang.mixin(this, params);
                        if(this.id){
                                registry.add(this); // add to registry so it can be easily found by id
                        }
                        this.domNode.style.display = "none";

                        this.inherited(arguments, [{
                                data: query("option", this.domNode).map(toItem)
                        }]);
                },

                destroy: function(){
                        registry.remove(this.id);
                },

                fetchSelectedItem: function(){
                        // summary:
                        //              Get the option marked as selected, like `<option selected>`.
                        //              Not part of dojo.data API.
                        var option = query("> option[selected]", this.domNode)[0] || query("> option", this.domNode)[0];
                        return option && toItem(option);
                }
        });
});