diff --git a/lib/sax.js b/lib/sax.js
index 795d607e..1322caeb 100644
--- a/lib/sax.js
+++ b/lib/sax.js
@@ -276,12 +276,56 @@
   // without a significant breaking change to either this  parser, or the
   // JavaScript language.  Implementation of an emoji-capable xml parser
   // is left as an exercise for the reader.
-  var nameStart = /[:_A-Za-z\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u02FF\u0370-\u037D\u037F-\u1FFF\u200C-\u200D\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD]/
 
-  var nameBody = /[:_A-Za-z\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u02FF\u0370-\u037D\u037F-\u1FFF\u200C-\u200D\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD\u00B7\u0300-\u036F\u203F-\u2040.\d-]/
+  function isNameStartCharCode (cc) {
+    return (cc >= 97 && cc <= 122) || // a-z
+      (cc >= 65 && cc <= 90) || // A-Z
+      cc === 58 || // :
+      cc === 95 || // _
+      (cc >= 0x00C0 && cc <= 0x00D6) ||
+      (cc >= 0x00D8 && cc <= 0x00F6) ||
+      (cc >= 0x00F8 && cc <= 0x02FF) ||
+      (cc >= 0x0370 && cc <= 0x037D) ||
+      (cc >= 0x037F && cc <= 0x1FFF) ||
+      (cc >= 0x200C && cc <= 0x200D) ||
+      (cc >= 0x2070 && cc <= 0x218F) ||
+      (cc >= 0x2C00 && cc <= 0x2FEF) ||
+      (cc >= 0x3001 && cc <= 0xD7FF) ||
+      (cc >= 0xF900 && cc <= 0xFDCF) ||
+      (cc >= 0xFDF0 && cc <= 0xFFFD)
+  }
+
+  function isNameBodyCharCode (cc) {
+    return isNameStartCharCode(cc) ||
+      cc === 45 || // -
+      cc === 46 || // .
+      (cc >= 48 && cc <= 57) || // 0-9
+      cc === 0x00B7 ||
+      (cc >= 0x0300 && cc <= 0x036F) ||
+      (cc >= 0x203F && cc <= 0x2040)
+  }
+
+  function isNameStart (c) {
+    var cc = c.charCodeAt(0)
+    return isNameStartCharCode(cc)
+  }
+
+  function isNameBody (c) {
+    var cc = c.charCodeAt(0)
+    return isNameBodyCharCode(cc)
+  }
 
-  var entityStart = /[#:_A-Za-z\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u02FF\u0370-\u037D\u037F-\u1FFF\u200C-\u200D\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD]/
-  var entityBody = /[#:_A-Za-z\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u02FF\u0370-\u037D\u037F-\u1FFF\u200C-\u200D\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD\u00B7\u0300-\u036F\u203F-\u2040.\d-]/
+  function isEntityStart (c) {
+    var cc = c.charCodeAt(0)
+    return cc === 35 || // #
+      isNameStartCharCode(cc)
+  }
+
+  function isEntityBody (c) {
+    var cc = c.charCodeAt(0)
+    return cc === 35 || // #
+      isNameBodyCharCode(cc)
+  }
 
   function isWhitespace (c) {
     return c === ' ' || c === '\n' || c === '\r' || c === '\t'
@@ -295,14 +339,6 @@
     return c === '>' || isWhitespace(c)
   }
 
-  function isMatch (regex, c) {
-    return regex.test(c)
-  }
-
-  function notMatch (regex, c) {
-    return !isMatch(regex, c)
-  }
-
   var S = 0
   sax.STATE = {
     BEGIN: S++, // leading byte order mark or whitespace
@@ -1067,7 +1103,7 @@
             parser.sgmlDecl = ''
           } else if (isWhitespace(c)) {
             // wait for it...
-          } else if (isMatch(nameStart, c)) {
+          } else if (isNameStart(c)) {
             parser.state = S.OPEN_TAG
             parser.tagName = c
           } else if (c === '/') {
@@ -1270,7 +1306,7 @@
           continue
 
         case S.OPEN_TAG:
-          if (isMatch(nameBody, c)) {
+          if (isNameBody(c)) {
             parser.tagName += c
           } else {
             newTag(parser)
@@ -1305,7 +1341,7 @@
             openTag(parser)
           } else if (c === '/') {
             parser.state = S.OPEN_TAG_SLASH
-          } else if (isMatch(nameStart, c)) {
+          } else if (isNameStart(c)) {
             parser.attribName = c
             parser.attribValue = ''
             parser.state = S.ATTRIB_NAME
@@ -1324,7 +1360,7 @@
             openTag(parser)
           } else if (isWhitespace(c)) {
             parser.state = S.ATTRIB_NAME_SAW_WHITE
-          } else if (isMatch(nameBody, c)) {
+          } else if (isNameBody(c)) {
             parser.attribName += c
           } else {
             strictFail(parser, 'Invalid attribute name')
@@ -1347,7 +1383,7 @@
             parser.attribName = ''
             if (c === '>') {
               openTag(parser)
-            } else if (isMatch(nameStart, c)) {
+            } else if (isNameStart(c)) {
               parser.attribName = c
               parser.state = S.ATTRIB_NAME
             } else {
@@ -1391,7 +1427,7 @@
             openTag(parser)
           } else if (c === '/') {
             parser.state = S.OPEN_TAG_SLASH
-          } else if (isMatch(nameStart, c)) {
+          } else if (isNameStart(c)) {
             strictFail(parser, 'No whitespace between attributes')
             parser.attribName = c
             parser.attribValue = ''
@@ -1422,7 +1458,7 @@
           if (!parser.tagName) {
             if (isWhitespace(c)) {
               continue
-            } else if (notMatch(nameStart, c)) {
+            } else if (!isNameStart(c)) {
               if (parser.script) {
                 parser.script += '</' + c
                 parser.state = S.SCRIPT
@@ -1434,7 +1470,7 @@
             }
           } else if (c === '>') {
             closeTag(parser)
-          } else if (isMatch(nameBody, c)) {
+          } else if (isNameBody(c)) {
             parser.tagName += c
           } else if (parser.script) {
             parser.script += '</' + parser.tagName
@@ -1485,7 +1521,7 @@
             parser[buffer] += parseEntity(parser)
             parser.entity = ''
             parser.state = returnState
-          } else if (isMatch(parser.entity.length ? entityBody : entityStart, c)) {
+          } else if (parser.entity.length ? isEntityBody(c) : isEntityStart(c)) {
             parser.entity += c
           } else {
             strictFail(parser, 'Invalid character in entity name')