added popular pseudo-element selectors '::after', '::before', '::firs…

…t-letter', '::first-line', '::selection', '::backdrop' and '::placeholder' to avoid runtime errors while parsing valid CSS syntax. These elements generate dynamic content without inserting new nodes and will not modify the DOM tree, thus for these selectors the 'select()' method will always return an empty array while the 'match' method will always return false.

src/modules/nwmatcher-pseudos.js

@@ -271,3 +271,38 @@ NW.Dom.registerSelector(
     };
 
   })(this));
+
+NW.Dom.registerSelector(
+  'nwmatcher:epseudos',
+  /^((?:[:]{1,2}(?:after|before|first-letter|first-line))|(?:[:]{2,2}(?:selection|backdrop|placeholder)))?(.*)/i,
+  (function(global) {
+
+    return function(match, source) {
+
+      var status = true;
+
+      switch (match[1].match(/(\w+)$/)[0]) {
+
+        case 'after':
+        case 'before':
+        case 'first-letter':
+        case 'first-line':
+        case 'selection':
+        case 'backdrop':
+        case 'placeholder':
+          source = 'if(!(/1|11/).test(e.nodeType)){' + source + '}';
+          break;
+
+        default:
+          status = false;
+          break;
+      }
+
+      return {
+        'source': source,
+        'status': status
+      };
+
+    };
+
+  })(this));

src/nwmatcher-base.js

@@ -46,7 +46,7 @@
   lastPartsMatch,
   lastPartsSelect,
 
-  prefixes = '[#.:]?',
+  prefixes = '(?:[#.:]|::)?',
   operators = '([~*^$|!]?={1})',
   whitespace = '[\\x20\\t\\n\\r\\f]',
   combinators = '\\x20|[>+~](?=[^>+~])',

src/nwmatcher-noqsa.js

@@ -46,7 +46,7 @@
   lastPartsMatch,
   lastPartsSelect,
 
-  prefixes = '[#.:]?',
+  prefixes = '(?:[#.:]|::)?',
   operators = '([~*^$|!]?={1})',
   whitespace = '[\\x20\\t\\n\\r\\f]',
   combinators = '\\x20|[>+~](?=[^>+~])',
@@ -78,6 +78,7 @@
   Patterns = {
     spseudos: /^\:(root|empty|(?:first|last|only)(?:-child|-of-type)|nth(?:-last)?(?:-child|-of-type)\(\s*(even|odd|(?:[-+]{0,1}\d*n\s*)?[-+]{0,1}\s*\d*)\s*\))?(.*)/i,
     dpseudos: /^\:(link|visited|target|active|focus|hover|checked|disabled|enabled|selected|lang\(([-\w]{2,})\)|not\(\s*(:nth(?:-last)?(?:-child|-of-type)\(\s*(?:even|odd|(?:[-+]{0,1}\d*n\s*)?[-+]{0,1}\s*\d*)\s*\)|[^()]*)\s*\))?(.*)/i,
+    epseudos: /^((?:[:]{1,2}(?:after|before|first-letter|first-line))|(?:[:]{2,2}(?:selection|backdrop|placeholder)))?(.*)/i,
     children: RegExp('^' + whitespace + '*\\>' + whitespace + '*(.*)'),
     adjacent: RegExp('^' + whitespace + '*\\+' + whitespace + '*(.*)'),
     relative: RegExp('^' + whitespace + '*\\~' + whitespace + '*(.*)'),
@@ -688,6 +689,10 @@
           }
         }
 
+        else if ((match = selector.match(Patterns.epseudos)) && match[1]) {
+          source = 'if(!(/1|11/).test(e.nodeType)){' + source + '}';
+        }
+
         else {
 
           expr = false;

src/nwmatcher.js

@@ -53,7 +53,7 @@
 
   // accepted prefix identifiers
   // (id, class & pseudo-class)
-  prefixes = '[#.:]?',
+  prefixes = '(?:[#.:]|::)?',
 
   // accepted attribute operators
   operators = '([~*^$|!]?={1})',
@@ -124,6 +124,8 @@
     spseudos: /^\:(root|empty|(?:first|last|only)(?:-child|-of-type)|nth(?:-last)?(?:-child|-of-type)\(\s*(even|odd|(?:[-+]{0,1}\d*n\s*)?[-+]{0,1}\s*\d*)\s*\))?(.*)/i,
     // uistates + dynamic + negation pseudo-classes
     dpseudos: /^\:(link|visited|target|active|focus|hover|checked|disabled|enabled|selected|lang\(([-\w]{2,})\)|not\(\s*(:nth(?:-last)?(?:-child|-of-type)\(\s*(?:even|odd|(?:[-+]{0,1}\d*n\s*)?[-+]{0,1}\s*\d*)\s*\)|[^()]*)\s*\))?(.*)/i,
+    // pseudo-elements selectors
+    epseudos: /^((?:[:]{1,2}(?:after|before|first-letter|first-line))|(?:[:]{2,2}(?:selection|backdrop|placeholder)))?(.*)/i,
     // E > F
     children: RegExp('^' + whitespace + '*\\>' + whitespace + '*(.*)'),
     // E + F
@@ -1337,6 +1339,10 @@
 
         }
 
+        else if ((match = selector.match(Patterns.epseudos)) && match[1]) {
+          source = 'if(!(/1|11/).test(e.nodeType)){' + source + '}';
+        }
+
         else {
 
           // this is where external extensions are