_ToggleButtonMixin.js

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

	// module:
	//		dijit/form/_ToggleButtonMixin

	return declare("dijit.form._ToggleButtonMixin", null, {
		// summary:
		//		A mixin to provide functionality to allow a button that can be in two states (checked or not).

		// checked: Boolean
		//		Corresponds to the native HTML `<input>` element's attribute.
		//		In markup, specified as "checked='checked'" or just "checked".
		//		True if the button is depressed, or the checkbox is checked,
		//		or the radio button is selected, etc.
		checked: false,

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

		_onClick: function(/*Event*/ evt){
			var original = this.checked;
			this._set('checked', !original); // partially set the toggled value, assuming the toggle will work, so it can be overridden in the onclick handler
			var ret = this.inherited(arguments); // the user could reset the value here
			this.set('checked', ret ? this.checked : original); // officially set the toggled or user value, or reset it back
			return ret;
		},

		_setCheckedAttr: function(/*Boolean*/ value, /*Boolean?*/ priorityChange){
			this._set("checked", value);
			var node = this.focusNode || this.domNode;
			if(this._created){ // IE is not ready to handle checked attribute (affects tab order)
				// needlessly setting "checked" upsets IE's tab order
				if(domAttr.get(node, "checked") != !!value){
					domAttr.set(node, "checked", !!value); // "mixed" -> true
				}
			}
			node.setAttribute(this._aria_attr, String(value)); // aria values should be strings
			this._handleOnChange(value, priorityChange);
		},

		postCreate: function(){ // use postCreate instead of startup so users forgetting to call startup are OK
			this.inherited(arguments);
			var node = this.focusNode || this.domNode;
			if(this.checked){
				// need this here instead of on the template so IE8 tab order works
				node.setAttribute('checked', 'checked');
			}

			// Update our reset value if it hasn't yet been set (because this.set()
			// is only called when there *is* a value)
			if(this._resetValue === undefined){
				this._lastValueReported = this._resetValue = this.checked;
			}
		},

		reset: function(){
			// summary:
			//		Reset the widget's value to what it was at initialization time

			this._hasBeenBlurred = false;

			// set checked state to original setting
			this.set('checked', this.params.checked || false);
		}
	});
});