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

define([
        "dojo/_base/declare", // declare
        "dojo/dom-attr" // domAttr.set
], function(declare, domAttr){

        // module:
        //              dijit/form/_CheckBoxMixin

        return declare("dijit.form._CheckBoxMixin", null, {
                // summary:
                //              Mixin to provide widget functionality corresponding to an HTML checkbox
                //
                // description:
                //              User interacts with real html inputs.
                //              On onclick (which occurs by mouse click, space-bar, or
                //              using the arrow keys to switch the selected radio button),
                //              we update the state of the checkbox/radio.
                //

                // type: [private] String
                //              type attribute on `<input>` node.
                //              Overrides `dijit/form/Button.type`.  Users should not change this value.
                type: "checkbox",

                // value: String
                //              As an initialization parameter, equivalent to value field on normal checkbox
                //              (if checked, the value is passed as the value when form is submitted).
                value: "on",

                // readOnly: Boolean
                //              Should this widget respond to user input?
                //              In markup, this is specified as "readOnly".
                //              Similar to disabled except readOnly form values are submitted.
                readOnly: false,

                // aria-pressed for toggle buttons, and aria-checked for checkboxes
                _aria_attr: "aria-checked",

                _setReadOnlyAttr: function(/*Boolean*/ value){
                        this._set("readOnly", value);
                        domAttr.set(this.focusNode, 'readOnly', value);
                },

                // Override dijit/form/Button._setLabelAttr() since we don't even have a containerNode.
                // Normally users won't try to set label, except when CheckBox or RadioButton is the child of a dojox/layout/TabContainer
                _setLabelAttr: undefined,

                _getSubmitValue: function(/*String*/ value){
                        return (value == null || value === "") ? "on" : value;
                },

                _setValueAttr: function(newValue){
                        newValue = this._getSubmitValue(newValue);      // "on" to match browser native behavior when value unspecified
                        this._set("value", newValue);
                        domAttr.set(this.focusNode, "value", newValue);
                },

                reset: function(){
                        this.inherited(arguments);
                        // Handle unlikely event that the <input type=checkbox> value attribute has changed
                        this._set("value", this._getSubmitValue(this.params.value));
                        domAttr.set(this.focusNode, 'value', this.value);
                },

                _onClick: function(/*Event*/ e){
                        // summary:
                        //              Internal function to handle click actions - need to check
                        //              readOnly, since button no longer does that check.
                        if(this.readOnly){
                                e.stopPropagation();
                                e.preventDefault();
                                return false;
                        }
                        return this.inherited(arguments);
                }
        });
});