diff --git a/ui/jquery.ui.datepicker.js b/ui/jquery.ui.datepicker.js
index ccbcc6dac24..678129e4904 100644
--- a/ui/jquery.ui.datepicker.js
+++ b/ui/jquery.ui.datepicker.js
@@ -167,7 +167,7 @@ $.extend(Datepicker.prototype, {
 
 	/* Create a new instance object. */
 	_newInst: function(target, inline) {
-		var id = target[0].id.replace(/([^A-Za-z0-9_])/g, '\\\\$1'); // escape jQuery meta chars
+		var id = target[0].id.replace(/([^A-Za-z0-9_-])/g, '\\\\$1'); // escape jQuery meta chars
 		return {id: id, input: target, // associated target
 			selectedDay: 0, selectedMonth: 0, selectedYear: 0, // current selection
 			drawMonth: 0, drawYear: 0, // month being drawn