diff --git a/docs/dtd/xhtml1-purified.dtd b/docs/dtd/xhtml1-purified.dtd
index 8751b294..abffd273 100644
--- a/docs/dtd/xhtml1-purified.dtd
+++ b/docs/dtd/xhtml1-purified.dtd
@@ -74,14 +74,14 @@ be translated intelligently -->
   >
 
 <!ATTLIST bdo
-  %coreattrs;
+  %coreattrs; // !#!
   lang        %LanguageCode; #IMPLIED
   xml:lang    %LanguageCode; #IMPLIED
   dir         (ltr|rtl)      #REQUIRED
   >
 
 <!ATTLIST br
-  %coreattrs;
+  %coreattrs; // !#!
   DEPRECATED clear       (left|all|right|none) "none"
   >
 
diff --git a/library/HTMLPurifier/Definition.php b/library/HTMLPurifier/Definition.php
index acbcbbbc..6012bec3 100644
--- a/library/HTMLPurifier/Definition.php
+++ b/library/HTMLPurifier/Definition.php
@@ -1,6 +1,8 @@
 <?php
 
 require_once 'HTMLPurifier/AttrDef.php';
+    require_once 'HTMLPurifier/AttrDef/Enum.php';
+    require_once 'HTMLPurifier/AttrDef/ID.php';
 require_once 'HTMLPurifier/ChildDef.php';
 require_once 'HTMLPurifier/Generator.php';
 require_once 'HTMLPurifier/Token.php';
@@ -156,8 +158,16 @@ class HTMLPurifier_Definition
         $this->info['child']['a']    = $e_a_content;
         
         // attribute info
+        // this doesn't include REQUIRED declarations, those are handled
+        // by the transform classes
         
-        $a_dir = new HTMLPurifier_AttrDef_Enum(array('ltr','rtl'), false);
+        // attrs, included in almost every single one except for a few
+        $this->info['attr']['*'] = array(
+            // core attrs
+            'id' => new HTMLPurifier_AttrDef_ID(),
+            // i18n
+            'dir' => new HTMLPurifier_AttrDef_Enum(array('ltr','rtl'), false),
+            );
         
     }
     
diff --git a/library/HTMLPurifier/Generator.php b/library/HTMLPurifier/Generator.php
index d8eabd61..deecc084 100644
--- a/library/HTMLPurifier/Generator.php
+++ b/library/HTMLPurifier/Generator.php
@@ -5,6 +5,7 @@ class HTMLPurifier_Generator
     
     function generateFromTokens($tokens) {
         $html = '';
+        if (!$tokens) return '';
         foreach ($tokens as $token) {
             $html .= $this->generateFromToken($token);
         }
diff --git a/library/HTMLPurifier/Strategy/ValidateAttributes.php b/library/HTMLPurifier/Strategy/ValidateAttributes.php
new file mode 100644
index 00000000..e36dcb3c
--- /dev/null
+++ b/library/HTMLPurifier/Strategy/ValidateAttributes.php
@@ -0,0 +1,52 @@
+<?php
+
+require_once 'HTMLPurifier/Strategy.php';
+require_once 'HTMLPurifier/Definition.php';
+require_once 'HTMLPurifier/IDAccumulator.php';
+
+class HTMLPurifier_Strategy_ValidateAttributes extends HTMLPurifier_Strategy
+{
+    
+    var $definition;
+    
+    function HTMLPurifier_Strategy_ValidateAttributes() {
+        $this->definition = HTMLPurifier_Definition::instance();
+    }
+    
+    function execute($tokens) {
+        $accumulator = new HTMLPurifier_IDAccumulator();
+        $d_defs = $this->definition->info['attr']['*'];
+        foreach ($tokens as $key => $token) {
+            if ($token->type !== 'start' && $token->type !== 'end') continue;
+            $name = $token->name;
+            $attr = $token->attributes;
+            $defs = isset($this->definition->info['attr'][$name]) ?
+                $this->definition->attr[$name] : array();
+            $changed = false;
+            foreach ($attr as $attr_key => $value) {
+                if ( isset($defs[$attr_key]) ) {
+                    if (!$defs[$attr_key]) {
+                        $result = false;
+                    } else {
+                        $result = $defs[$attr_key]->validate($value, $accumulator);
+                    }
+                } elseif ( isset($d_defs[$attr_key]) ) {
+                    $result = $d_defs[$attr_key]->validate($value, $accumulator);
+                } else {
+                    $result = false;
+                }
+                if (!$result) {
+                    $changed = true;
+                    unset($attr[$attr_key]);
+                }
+            }
+            if ($changed) {
+                $tokens[$key]->attributes = $attr;
+            }
+        }
+        return $tokens;
+    }
+    
+}
+
+?>
\ No newline at end of file
diff --git a/tests/HTMLPurifier/GeneratorTest.php b/tests/HTMLPurifier/GeneratorTest.php
index ac1bb0c1..d93decf0 100644
--- a/tests/HTMLPurifier/GeneratorTest.php
+++ b/tests/HTMLPurifier/GeneratorTest.php
@@ -74,13 +74,25 @@ class HTMLPurifier_GeneratorTest extends UnitTestCase
     
     function test_generateFromTokens() {
         
-        $tokens = array(
+        $inputs = array();
+        $expect = array();
+        
+        $inputs[0] = array(
             new HTMLPurifier_Token_Start('b'),
             new HTMLPurifier_Token_Text('Foobar!'),
             new HTMLPurifier_Token_End('b')
             );
-        $expect = '<b>Foobar!</b>';
-        $this->assertEqual($expect, $this->gen->generateFromTokens($tokens));
+        $expect[0] = '<b>Foobar!</b>';
+        
+        $inputs[1] = array();
+        $expect[1] = '';
+        
+        foreach ($inputs as $i => $input) {
+            $result = $this->gen->generateFromTokens($input);
+            $this->assertEqual($expect[$i], $result);
+            paintIf($result, $result != $expect[$i]);
+        }
+        
         
     }
     
diff --git a/tests/HTMLPurifier/Strategy/ValidateAttributesTest.php b/tests/HTMLPurifier/Strategy/ValidateAttributesTest.php
new file mode 100644
index 00000000..f79bdb81
--- /dev/null
+++ b/tests/HTMLPurifier/Strategy/ValidateAttributesTest.php
@@ -0,0 +1,39 @@
+<?php
+
+require_once('HTMLPurifier/StrategyAbstractTest.php');
+require_once('HTMLPurifier/Strategy/ValidateAttributes.php');
+
+class HTMLPurifier_Strategy_ValidateAttributesTest extends
+      HTMLPurifier_StrategyAbstractTest
+{
+    
+    function test() {
+        
+        $strategy = new HTMLPurifier_Strategy_ValidateAttributes();
+        
+        $inputs = array();
+        $expect = array();
+        
+        $inputs[0] = '';
+        $expect[0] = '';
+        
+        $inputs[1] = '<div id="valid">Preserve the ID.</div>';
+        $expect[1] = $inputs[1];
+        
+        $inputs[2] = '<div id="0invalid">Kill the ID.</div>';
+        $expect[2] = '<div>Kill the ID.</div>';
+        
+        // test accumulator
+        $inputs[3] = '<div id="valid">Valid</div><div id="valid">Invalid</div>';
+        $expect[3] = '<div id="valid">Valid</div><div>Invalid</div>';
+        
+        $inputs[4] = '<span dir="up-to-down">Bad dir.</span>';
+        $expect[4] = '<span>Bad dir.</span>';
+        
+        $this->assertStrategyWorks($strategy, $inputs, $expect);
+        
+    }
+    
+}
+
+?>
\ No newline at end of file
diff --git a/tests/index.php b/tests/index.php
index d87e2d0d..1c152605 100644
--- a/tests/index.php
+++ b/tests/index.php
@@ -32,6 +32,7 @@ $test->addTestFile('HTMLPurifier/Strategy/MakeWellFormedTest.php');
 $test->addTestFile('HTMLPurifier/Strategy/FixNestingTest.php');
 $test->addTestFile('HTMLPurifier/Strategy/CompositeTest.php');
 $test->addTestFile('HTMLPurifier/Strategy/CoreTest.php');
+$test->addTestFile('HTMLPurifier/Strategy/ValidateAttributesTest.php');
 $test->addTestFile('HTMLPurifier/AttrDef/EnumTest.php');
 $test->addTestFile('HTMLPurifier/AttrDef/IDTest.php');
 $test->addTestFile('HTMLPurifier/IDAccumulatorTest.php');