diff --git a/library/HTML5/TreeBuilder.php b/library/HTML5/TreeBuilder.php
index 578e73682..2a789f4df 100644
--- a/library/HTML5/TreeBuilder.php
+++ b/library/HTML5/TreeBuilder.php
@@ -158,6 +158,8 @@ class HTML5_TreeBuilder {
 
         if ($this->ignore_lf_token) $this->ignore_lf_token--;
         $this->ignored = false;
+
+        $token['name'] = str_replace(':', '-', $token['name']);
         // indenting is a little wonky, this can be changed later on
         switch ($mode) {
 
@@ -1429,7 +1431,7 @@ class HTML5_TreeBuilder {
                 case 'tbody': case 'td': case 'tfoot': case 'th': case 'thead': case 'tr':
                     // parse error
                 break;
-
+                
                 /* A start tag token not covered by the previous entries */
                 default:
                     /* Reconstruct the active formatting elements, if any. */
@@ -3038,7 +3040,7 @@ class HTML5_TreeBuilder {
 
     private function insertElement($token, $append = true) {
         $el = $this->dom->createElementNS(self::NS_HTML, $token['name']);
-
+		
         if (!empty($token['attr'])) {
             foreach($token['attr'] as $attr) {