Merge branch '4321' of https://github.com/rwldrn/jquery into rwldrn-4321

diff --cc src/core.js
index d8ed38c5040b7705efdbfb4b79be7516b254b208,3a4d9e66922fae137a09211036dc2f900838eadb..f19de96d01da062d03e32b55c1f3405fe5bdda70
--- 1/src/core.js
--- 2/src/core.js
+++ b/src/core.js
@@@ -17,10 -17,14 +17,10 @@@ var jQuery = function( selector, contex
  
        // A simple way to check for HTML strings or ID strings
        // (both of which we optimize for)
-       quickExpr = /^(?:[^<]*(<[\w\W]+>)[^>]*$|#([\w\-]+)$)/,
+       quickExpr = /^(?:[^<]*(<[\w\W]+>)[^>]*$|#([\w\-]*)$)/,
  
 -      // Is it a simple selector
 -      isSimple = /^.[^:#\[\.,]*$/,
 -
        // Check if a string has a non-whitespace character in it
        rnotwhite = /\S/,
 -      rwhite = /\s/,
  
        // Used for trimming whitespace
        trimLeft = /^\s+/,

diff --cc test/unit/core.js
index 6ee8724de977069cea375ff39ebbc52688c39d6f,2563f17cb4a48d314f9ea4613938fd8a983c3f39..a8da85fc25fc44f267d4afe97e5b5b904648d0b4
--- 1/test/unit/core.js
--- 2/test/unit/core.js
+++ b/test/unit/core.js
@@@ -12,16 -12,19 +12,17 @@@ test("Basic requirements", function() 
  });
  
  test("jQuery()", function() {
-       expect(24);
+       expect(25);
  
 -      strictEqual( commonJSDefined, jQuery, "CommonJS registered (Bug #7102)" );
 -
        // Basic constructor's behavior
  
        equals( jQuery().length, 0, "jQuery() === jQuery([])" );
        equals( jQuery(undefined).length, 0, "jQuery(undefined) === jQuery([])" );
        equals( jQuery(null).length, 0, "jQuery(null) === jQuery([])" );
        equals( jQuery("").length, 0, "jQuery('') === jQuery([])" );
+       equals( jQuery("#").length, 0, "jQuery('#') === jQuery([])" );
  
 -      var obj = jQuery("div")
 +      var obj = jQuery("div");
        equals( jQuery(obj).selector, "div", "jQuery(jQueryObj) == jQueryObj" );
  
                // can actually yield more than one, when iframes are included, the window is an array as well