diff --git a/js/jquery.mobile.forms.slider.js b/js/jquery.mobile.forms.slider.js
index 41bff807..2a0453b7 100644
--- a/js/jquery.mobile.forms.slider.js
+++ b/js/jquery.mobile.forms.slider.js
@@ -269,7 +269,7 @@ $.widget( "mobile.slider", $.mobile.widget, {
 			percent = Math.round( ( ( data.pageX - this.slider.offset().left ) / this.slider.width() ) * 100 );
 		} else {
 			if ( val == null ) {
-				val = cType === "input" ? parseFloat( control.val() ) : control[0].selectedIndex;
+				val = cType === "input" ? parseFloat( control.val() || 0 ) : control[0].selectedIndex;
 			}
 			percent = ( parseFloat( val ) - min ) / ( max - min ) * 100;
 		}