Fixed an issue with setting offset of absolutely positioned element that has no position values ("auto"). Fixes #5781.

1 files changed, 18 insertions, 6 deletions

diff --git a/src/offset.js b/src/offset.js
index 59591caea..0ce4c1979 100644
--- a/src/offset.js
+++ b/src/offset.js
@@ -150,15 +150,27 @@ jQuery.offset = {
 	},
 	
 	setOffset: function( elem, options, i ) {
+		var position = jQuery.curCSS( elem, "position" );
+
 		// set position first, in-case top/left are set even on static elem
-		if ( /static/.test( jQuery.curCSS( elem, "position" ) ) ) {
+		if ( position === "static" ) {
 			elem.style.position = "relative";
 		}
-		var curElem   = jQuery( elem ),
-			curOffset = curElem.offset(),
-			curTop    = parseInt( jQuery.curCSS( elem, "top",  true ), 10 ) || 0,
-			curLeft   = parseInt( jQuery.curCSS( elem, "left", true ), 10 ) || 0,
-			props     = {};
+
+		var curElem    = jQuery( elem ),
+			curOffset  = curElem.offset(),
+			curCSSTop  = jQuery.curCSS( elem, "top", true ),
+			curCSSLeft = jQuery.curCSS( elem, "left", true ),
+			calculatePosition = (position === "absolute" && jQuery.inArray('auto', [curCSSTop, curCSSLeft]) > -1),
+			props = {}, curPosition = {}, curTop, curLeft;
+
+		// need to be able to calculate position if either top or left is auto and position is absolute
+		if ( calculatePosition ) {
+			curPosition = curElem.position();
+		}
+
+		curTop  = calculatePosition ? curPosition.top  : parseInt( curCSSTop,  10 ) || 0;
+		curLeft = calculatePosition ? curPosition.left : parseInt( curCSSLeft, 10 ) || 0;
 
 		if ( jQuery.isFunction( options ) ) {
 			options = options.call( elem, i, curOffset );