Landed cross-browser support for tabIndex, by Scott, closes ticket #3649.

src/core.js

@@ -970,6 +970,13 @@ jQuery.extend({
 				if( jQuery.nodeName( elem, "form" ) && elem.getAttributeNode(name) )
 					return elem.getAttributeNode( name ).nodeValue;
 
+				// elem.tabindex doesn't always return the correct value
+				// http://fluidproject.org/blog/2008/01/09/getting-setting-and-removing-tabindex-values-with-javascript/
+				if ( name == jQuery.props.tabindex ) {
+					var attributeNode = elem.getAttributeNode(jQuery.props.tabindex);
+					return attributeNode && attributeNode.specified && attributeNode.value || undefined;
+				}
+
 				return elem[ name ];
 			}
 

src/support.js

@@ -51,6 +51,10 @@
 		// (IE uses styleFloat instead of cssFloat)
 		cssFloat: !!a.style.cssFloat,
 
+		// Verify tabindex attribute existence
+		// (IE uses tabIndex instead of tabindex)
+		tabindex: !a.getAttributeNode('tabindex'),
+
 		// Will be defined later
 		scriptEval: false,
 		noCloneEvent: true
@@ -96,5 +100,6 @@ jQuery.props = {
 	readonly: "readOnly",
 	maxlength: "maxLength",
 	cellspacing: "cellSpacing",
-	rowspan: "rowSpan"
+	rowspan: "rowSpan",
+	tabindex: jQuery.support.tabindex ? "tabindex" : "tabIndex"
 };