- for ( var i = 0; i < ret.length; i++ )
- r = jQuery.merge( r,
- m[2] == "*" ?
- jQuery.getAll(ret[i]) :
- ret[i].getElementsByTagName(m[2])
+ // Try to do a global search by ID, where we can
+ if ( m[1] == "#" && ret[ret.length-1].getElementById ) {
+ // Optimization for HTML document case
+ var oid = ret[ret.length-1].getElementById(m[2]);
+
+ // Do a quick check for node name (where applicable) so
+ // that div#foo searches will be really fast
+ ret = r = oid &&
+ (!m[3] || oid.nodeName == m[3].toUpperCase()) ? [oid] : [];
+
+ // Use the DOM 0 shortcut for the body element
+ } else if ( m[1] == "" && m[2] == "body" ) {
+ ret = r = [ document.body ];
+
+ } else {
+ // Pre-compile a regular expression to handle class searches
+ if ( m[1] == "." )
+ var rec = new RegExp("(^|\\s)" + m[2] + "(\\s|$)");
+
+ // We need to find all descendant elements, it is more
+ // efficient to use getAll() when we are already further down
+ // the tree - we try to recognize that here
+ for ( var i = 0, rl = ret.length; i < rl; i++ )
+ jQuery.merge( r,
+ m[1] != "" && ret.length != 1 ?
+ jQuery.getAll( ret[i], [], m[1], m[2], rec ) :
+ ret[i].getElementsByTagName( m[1] != "" || m[0] == "" ? "*" : m[2] )