Index: wp-includes/js/admin-bar.js
===================================================================
--- wp-includes/js/admin-bar.js	(revision 23005)
+++ wp-includes/js/admin-bar.js	(working copy)
@@ -130,6 +130,17 @@
 				}, 100);
 			}
 		});
+
+		// Attempt to work around a nasty long-standing bug with position: fixed in iOS Safari
+		// set #wpadminbar to position: absolute while a text field or textarea has focus
+		// (prevents it from jumping around and even covering the focused field)
+		if ( /Mobile\/.+Safari/.test(window.navigator.userAgent) ) {
+			$('input, textarea').focus(function(e){
+				$('#wpadminbar').css({left: 0, top: '-28px', position: 'absolute'});
+			}).blur(function(e){
+				$('#wpadminbar').css({left: '', top: '', position: ''});
+			});
+		}
 	});
 } else {
 	(function(d, w) {