diff --git a/ui/ui.slider.js b/ui/ui.slider.js
index 73877a21e..44936a8e5 100644
--- a/ui/ui.slider.js
+++ b/ui/ui.slider.js
@@ -204,8 +204,8 @@ $.widget("ui.slider", {
 	updateRange: function() {
 			var prop = this.options.axis == "vertical" ? "top" : "left";
 			var size = this.options.axis == "vertical" ? "height" : "width";
-			this.rangeElement.css(prop, parseInt($(this.handle[0]).css(prop),10) + this.handleSize(0, this.options.axis == "vertical" ? "y" : "x")/2);
-			this.rangeElement.css(size, parseInt($(this.handle[1]).css(prop),10) - parseInt($(this.handle[0]).css(prop),10));
+			this.rangeElement.css(prop, (parseInt($(this.handle[0]).css(prop),10) || 0) + this.handleSize(0, this.options.axis == "vertical" ? "y" : "x")/2);
+			this.rangeElement.css(size, (parseInt($(this.handle[1]).css(prop),10) || 0) - (parseInt($(this.handle[0]).css(prop),10) || 0));
 	},
 	getRange: function() {
 		return this.rangeElement ? this.convertValue(parseInt(this.rangeElement.css(this.options.axis == "vertical" ? "height" : "width"),10), this.options.axis == "vertical" ? "y" : "x") : null;