Index: jquery/test/unit/core.js
===================================================================
--- jquery/test/unit/core.js	(revision 5830)
+++ jquery/test/unit/core.js	(working copy)
@@ -217,6 +217,16 @@
 	ok( !jQuery("<option>test</option>")[0].selected, "Make sure that options are auto-selected #2050" );
 });
 
+test("jQuery(selector, 'html')", function() {
+	expect(2);
+	var teststring = '';
+	for (var i = 0; i < 10000; i++) { teststring += '22222222'; }
+	var htmlcode = '<div><div id="one">one</div><div id="two">' + teststring + '</div></div>';
+
+	equals(jQuery('#one', htmlcode).length, 1, "Verify that a selector matching against an HTML blob matches the correct number of times, #3178");
+	equals(jQuery('#one', htmlcode).html(), 'one', "Verify that a selector matching against an HTML blob reads correctly, #3178");
+});
+
 test("jQuery('html', context)", function() {
 	expect(1);
 
Index: jquery/src/core.js
===================================================================
--- jquery/src/core.js	(revision 5830)
+++ jquery/src/core.js	(working copy)
@@ -42,8 +42,10 @@
 		}
 		// Handle HTML strings
 		if ( typeof selector == "string" ) {
-			// Are we dealing with HTML string or an ID?
-			var match = quickExpr.exec( selector );
+			// Are we dealing with an HTML string or an ID?
+			// If selector.length is > 49996, Safari chokes (#3178).
+			// Assume that anything near that length is HTML.
+			var match = selector.length > 40000 ? { 1: selector } : quickExpr.exec( selector );
 
 			// Verify a match, and that no context was specified for #id
 			if ( match && (match[1] || !context) ) {