YUI Library Examples: Button Control: Calendar Menu Button with Date on Button Face

Begin by defining an anonymous function in order to keep all variables out of the global scope. Inside the anonymous function, define some shortcuts to utils that will be used frequently (Dom and Event).


1	(function () {
2
3	var Event = YAHOO.util.Event,
4	Dom = YAHOO.util.Dom;
5
6	}());
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Inside the the anonymous function, use the onContentReady method of the Event utility to instantiate an Overlay and a Button when the "datefields" <fieldset> is available to be scripted. Additionally, create references to each of the form fields used to set the date. Each of the three date form fields are hidden and the Calendar will be used as a proxy for them.


1	Event.onDOMReady(function () {
2
3	var oCalendarMenu;
4
5
6	var oDateFields = Dom.get("datefields");
7	oMonthField = Dom.get("month"),
8	oDayField = Dom.get("day"),
9	oYearField = Dom.get("year");
10
11
12	// Hide the form fields used for the date so that they can be replaced by the
13	// calendar button.
14
15	oMonthField.style.display = "none";
16	oDayField.style.display = "none";
17	oYearField.style.display = "none";
18
19
20	// Create a Overlay instance to house the Calendar instance
21
22	oCalendarMenu = new YAHOO.widget.Overlay("calendarmenu", { visible: false });
23
24
25	// Create a Button instance of type "menu"
26
27	var oButton = new YAHOO.widget.Button({
28	type: "menu",
29	id: "calendarpicker",
30	label: "Choose A Date",
31	menu: oCalendarMenu,
32	container: "datefields" });
33
34	});
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Once the new Button is created, add a listener for its "appendTo" event that will be used to render its Overlay instance into the same DOM element specified as the containing element for the Button.


1	oButton.on("appendTo", function () {
2
3	// Create an empty body element for the Overlay instance in order
4	// to reserve space to render the Calendar instance into.
5
6	oCalendarMenu.setBody(" ");
7
8	oCalendarMenu.body.id = "calendarcontainer";
9
10	});
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Add a listener for the Button's "click" event that will be used to create a new Calendar instance. (Defering the creation and rendering of the Calendar until the firing of the "click" event improves the intial load time of the Button instance.)


1	var onButtonClick = function () {
2
3	// Create a Calendar instance and render it into the body
4	// element of the Overlay.
5
6	var oCalendar = new YAHOO.widget.Calendar("buttoncalendar", oCalendarMenu.body.id);
7
8	oCalendar.render();
9
10
11	// Subscribe to the Calendar instance's "select" event to
12	// update the Button instance's label when the user
13	// selects a date.
14
15	oCalendar.selectEvent.subscribe(function (p_sType, p_aArgs) {
16
17	var aDate,
18	nMonth,
19	nDay,
20	nYear;
21
22	if (p_aArgs) {
23
24	aDate = p_aArgs[0][0];
25
26	nMonth = aDate[1];
27	nDay = aDate[2];
28	nYear = aDate[0];
29
30	oButton.set("label", (nMonth + "/" + nDay + "/" + nYear));
31
32
33	// Sync the Calendar instance's selected date with the date form fields
34
35	Dom.get("month").selectedIndex = (nMonth - 1);
36	Dom.get("day").selectedIndex = (nDay - 1);
37	Dom.get("year").value = nYear;
38
39	}
40
41	oCalendarMenu.hide();
42
43	});
44
45
46	// Pressing the Esc key will hide the Calendar Menu and send focus back to
47	// its parent Button
48
49	Event.on(oCalendarMenu.element, "keydown", function (p_oEvent) {
50
51	if (Event.getCharCode(p_oEvent) === 27) {
52	oCalendarMenu.hide();
53	this.focus();
54	}
55
56	}, null, this);
57
58
59	var focusDay = function () {
60
61	var oCalendarTBody = Dom.get("buttoncalendar").tBodies[0],
62	aElements = oCalendarTBody.getElementsByTagName("a"),
63	oAnchor;
64
65
66	if (aElements.length > 0) {
67
68	Dom.batch(aElements, function (element) {
69
70	if (Dom.hasClass(element.parentNode, "today")) {
71	oAnchor = element;
72	}
73
74	});
75
76
77	if (!oAnchor) {
78	oAnchor = aElements[0];
79	}
80
81
82	// Focus the anchor element using a timer since Calendar will try
83	// to set focus to its next button by default
84
85	YAHOO.lang.later(0, oAnchor, function () {
86	try {
87	oAnchor.focus();
88	}
89	catch(e) {}
90	});
91
92	}
93
94	};
95
96
97	// Set focus to either the current day, or first day of the month in
98	// the Calendar when it is made visible or the month changes
99
100	oCalendarMenu.subscribe("show", focusDay);
101	oCalendar.renderEvent.subscribe(focusDay, oCalendar, true);
102
103
104	// Give the Calendar an initial focus
105
106	focusDay.call(oCalendar);
107
108
109	// Re-align the CalendarMenu to the Button to ensure that it is in the correct
110	// position when it is initial made visible
111
112	oCalendarMenu.align();
113
114
115	// Unsubscribe from the "click" event so that this code is
116	// only executed once
117
118	this.unsubscribe("click", onButtonClick);
119
120	};
121
122
123	/*
124	Add a listener for the "click" event. This listener will be
125	used to defer the creation the Calendar instance until the
126	first time the Button's Overlay instance is requested to be displayed
127	by the user.
128	*/
129
130	oButton.on("click", onButtonClick);
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var onButtonClick = function () {

// Create a Calendar instance and render it into the body 
	// element of the Overlay.

var oCalendar = new YAHOO.widget.Calendar("buttoncalendar", oCalendarMenu.body.id);

oCalendar.render();

// Subscribe to the Calendar instance's "select" event to 
	// update the Button instance's label when the user
	// selects a date.

oCalendar.selectEvent.subscribe(function (p_sType, p_aArgs) {

var aDate,
			nMonth,
			nDay,
			nYear;

if (p_aArgs) {
			
			aDate = p_aArgs[0][0];

nMonth = aDate[1];
			nDay = aDate[2];
			nYear = aDate[0];

oButton.set("label", (nMonth + "/" + nDay + "/" + nYear));

// Sync the Calendar instance's selected date with the date form fields

Dom.get("month").selectedIndex = (nMonth - 1);
			Dom.get("day").selectedIndex = (nDay - 1);
			Dom.get("year").value = nYear;

}
		
		oCalendarMenu.hide();
	
	});

// Pressing the Esc key will hide the Calendar Menu and send focus back to 
	// its parent Button

Event.on(oCalendarMenu.element, "keydown", function (p_oEvent) {
	
		if (Event.getCharCode(p_oEvent) === 27) {
			oCalendarMenu.hide();
			this.focus();
		}
	
	}, null, this);
	
	
	var focusDay = function () {

var oCalendarTBody = Dom.get("buttoncalendar").tBodies[0],
			aElements = oCalendarTBody.getElementsByTagName("a"),
			oAnchor;

if (aElements.length > 0) {
		
			Dom.batch(aElements, function (element) {
			
				if (Dom.hasClass(element.parentNode, "today")) {
					oAnchor = element;
				}
			
			});
			
			
			if (!oAnchor) {
				oAnchor = aElements[0];
			}

// Focus the anchor element using a timer since Calendar will try 
			// to set focus to its next button by default
			
			YAHOO.lang.later(0, oAnchor, function () {
				try {
					oAnchor.focus();
				}
				catch(e) {}
			});
		
		}
		
	};

// Set focus to either the current day, or first day of the month in 
	// the Calendar	when it is made visible or the month changes

oCalendarMenu.subscribe("show", focusDay);
	oCalendar.renderEvent.subscribe(focusDay, oCalendar, true);

// Give the Calendar an initial focus
	
	focusDay.call(oCalendar);

// Re-align the CalendarMenu to the Button to ensure that it is in the correct
	// position when it is initial made visible
	
	oCalendarMenu.align();

// Unsubscribe from the "click" event so that this code is 
	// only executed once

this.unsubscribe("click", onButtonClick);

};

/*
	Add a listener for the "click" event.  This listener will be
	used to defer the creation the Calendar instance until the 
	first time the Button's Overlay instance is requested to be displayed
	by the user.
*/

oButton.on("click", onButtonClick);

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YUI Library Examples: Button Control: Calendar Menu Button with Date on Button Face

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