Datepicker: bind hover events using delegate. Fixed #7256 - minimize event binding in Datepicker initialization.

(cherry picked from commit 74d195e)

Author: adambaratz

ui/jquery.ui.datepicker.js

@@ -16,6 +16,7 @@ $.extend($.ui, { datepicker: { version: "@VERSION" } });
 
 var PROP_NAME = 'datepicker';
 var dpuuid = new Date().getTime();
+var instActive;
 
 /* Date picker manager.
    Use the singleton instance of this class, $.datepicker, to interact with the date picker.
@@ -107,7 +108,7 @@ function Datepicker() {
 		autoSize: false // True to size the input for the date format, false to leave as is
 	};
 	$.extend(this._defaults, this.regional['']);
-	this.dpDiv = $('<div id="' + this._mainDivId + '" class="ui-datepicker ui-widget ui-widget-content ui-helper-clearfix ui-corner-all"></div>');
+	this.dpDiv = bindHover($('<div id="' + this._mainDivId + '" class="ui-datepicker ui-widget ui-widget-content ui-helper-clearfix ui-corner-all"></div>'));
 }
 
 $.extend(Datepicker.prototype, {
@@ -173,7 +174,7 @@ $.extend(Datepicker.prototype, {
 			drawMonth: 0, drawYear: 0, // month being drawn
 			inline: inline, // is datepicker inline or not
 			dpDiv: (!inline ? this.dpDiv : // presentation div
-			$('<div class="' + this._inlineClass + ' ui-datepicker ui-widget ui-widget-content ui-helper-clearfix ui-corner-all"></div>'))};
+			bindHover($('<div class="' + this._inlineClass + ' ui-datepicker ui-widget ui-widget-content ui-helper-clearfix ui-corner-all"></div>')))};
 	},
 
 	/* Attach the date picker to an input field. */
@@ -672,29 +673,13 @@ $.extend(Datepicker.prototype, {
 	_updateDatepicker: function(inst) {
 		var self = this;
 		var borders = $.datepicker._getBorders(inst.dpDiv);
+		instActive = inst; // for delegate hover events
 		inst.dpDiv.empty().append(this._generateHTML(inst));
 		var cover = inst.dpDiv.find('iframe.ui-datepicker-cover'); // IE6- only
 		if( !!cover.length ){ //avoid call to outerXXXX() when not in IE6
 			cover.css({left: -borders[0], top: -borders[1], width: inst.dpDiv.outerWidth(), height: inst.dpDiv.outerHeight()})
 		}
-		inst.dpDiv.find('button, .ui-datepicker-prev, .ui-datepicker-next, .ui-datepicker-calendar td a')
-				.bind('mouseout', function(){
-					$(this).removeClass('ui-state-hover');
-					if(this.className.indexOf('ui-datepicker-prev') != -1) $(this).removeClass('ui-datepicker-prev-hover');
-					if(this.className.indexOf('ui-datepicker-next') != -1) $(this).removeClass('ui-datepicker-next-hover');
-				})
-				.bind('mouseover', function(){
-					if (!self._isDisabledDatepicker( inst.inline ? inst.dpDiv.parent()[0] : inst.input[0])) {
-						$(this).parents('.ui-datepicker-calendar').find('a').removeClass('ui-state-hover');
-						$(this).addClass('ui-state-hover');
-						if(this.className.indexOf('ui-datepicker-prev') != -1) $(this).addClass('ui-datepicker-prev-hover');
-						if(this.className.indexOf('ui-datepicker-next') != -1) $(this).addClass('ui-datepicker-next-hover');
-					}
-				})
-			.end()
-			.find('.' + this._dayOverClass + ' a')
-				.trigger('mouseover')
-			.end();
+		inst.dpDiv.find('.' + this._dayOverClass + ' a').mouseover();
 		var numMonths = this._getNumberOfMonths(inst);
 		var cols = numMonths[1];
 		var width = 17;
@@ -1715,6 +1700,28 @@ $.extend(Datepicker.prototype, {
 	}
 });
 
+/*
+ * Bind hover events for datepicker elements.
+ * Done via delegate so the binding only occurs once in the lifetime of the parent div.
+ * Global instActive, set by _updateDatepicker allows the handlers to find their way back to the active picker.
+ */ 
+function bindHover(dpDiv) {
+	var selector = 'button, .ui-datepicker-prev, .ui-datepicker-next, .ui-datepicker-calendar td a';
+	return dpDiv.delegate(selector, 'mouseout', function() {
+			$(this).removeClass('ui-state-hover');
+			if (this.className.indexOf('ui-datepicker-prev') != -1) $(this).removeClass('ui-datepicker-prev-hover');
+			if (this.className.indexOf('ui-datepicker-next') != -1) $(this).removeClass('ui-datepicker-next-hover');
+		})
+		.delegate(selector, 'mouseover', function(){
+			if (!$.datepicker._isDisabledDatepicker( instActive.inline ? dpDiv.parent()[0] : instActive.input[0])) {
+				$(this).parents('.ui-datepicker-calendar').find('a').removeClass('ui-state-hover');
+				$(this).addClass('ui-state-hover');
+				if (this.className.indexOf('ui-datepicker-prev') != -1) $(this).addClass('ui-datepicker-prev-hover');
+				if (this.className.indexOf('ui-datepicker-next') != -1) $(this).addClass('ui-datepicker-next-hover');
+			}
+		});
+}
+
 /* jQuery extend now ignores nulls! */
 function extendRemove(target, props) {
 	$.extend(target, props);