- if ( /static/.test( jQuery.curCSS( elem, 'position' ) ) ) {
- 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 = {
- top: (options.top - curOffset.top) + curTop,
- left: (options.left - curOffset.left) + curLeft
- };
+ if ( position === "static" ) {
+ elem.style.position = "relative";
+ }
+
+ 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 );
+ }
+
+ if (options.top != null) {
+ props.top = (options.top - curOffset.top) + curTop;
+ }
+ if (options.left != null) {
+ props.left = (options.left - curOffset.left) + curLeft;
+ }