diff --git a/library/HTMLPurifier/AttrDef/Composite.php b/library/HTMLPurifier/AttrDef/Composite.php
new file mode 100644
index 00000000..bf18b31c
--- /dev/null
+++ b/library/HTMLPurifier/AttrDef/Composite.php
@@ -0,0 +1,22 @@
+<?php
+
+class HTMLPurifier_AttrDef_Composite extends HTMLPurifier_AttrDef
+{
+    
+    var $defs;
+    
+    function HTMLPurifier_AttrDef_Composite(&$defs) {
+        $this->defs =& $defs;
+    }
+    
+    function validate($string, $config, &$context) {
+        foreach ($this->defs as $i => $def) {
+            $result = $this->defs[$i]->validate($string, $config, $context);
+            if ($result !== false) return $result;
+        }
+        return false;
+    }
+    
+}
+
+?>
\ No newline at end of file
diff --git a/tests/HTMLPurifier/AttrDef/CompositeTest.php b/tests/HTMLPurifier/AttrDef/CompositeTest.php
new file mode 100644
index 00000000..bd81db60
--- /dev/null
+++ b/tests/HTMLPurifier/AttrDef/CompositeTest.php
@@ -0,0 +1,81 @@
+<?php
+
+require_once 'HTMLPurifier/AttrDef/Composite.php';
+
+class HTMLPurifier_AttrDef_CompositeTest extends HTMLPurifier_AttrDefHarness
+{
+    
+    var $def1, $def2;
+    
+    function test() {
+        
+        generate_mock_once('HTMLPurifier_AttrDef');
+        
+        $config = HTMLPurifier_Config::createDefault();
+        $context = new HTMLPurifier_AttrContext();
+        
+        // first test: value properly validates on first definition
+        // so second def is never called
+        
+        $def1 =& new HTMLPurifier_AttrDefMock($this);
+        $def2 =& new HTMLPurifier_AttrDefMock($this);
+        $defs = array(&$def1, &$def2);
+        $def =& new HTMLPurifier_AttrDef_Composite($defs);
+        $input = 'FOOBAR';
+        $output = 'foobar';
+        $def1_params = array($input, $config, $context);
+        $def1->expectOnce('validate', $def1_params);
+        $def1->setReturnValue('validate', $output, $def1_params);
+        $def2->expectNever('validate');
+        
+        $this->assertIdentical($output,
+            $def->validate($input, $config, $context));
+        
+        $def1->tally();
+        $def2->tally();
+        
+        // second test, first def fails, second def works
+        
+        $def1 =& new HTMLPurifier_AttrDefMock($this);
+        $def2 =& new HTMLPurifier_AttrDefMock($this);
+        $defs = array(&$def1, &$def2);
+        $def =& new HTMLPurifier_AttrDef_Composite($defs);
+        $input = 'BOOMA';
+        $output = 'booma';
+        $def_params = array($input, $config, $context);
+        $def1->expectOnce('validate', $def_params);
+        $def1->setReturnValue('validate', false, $def_params);
+        $def2->expectOnce('validate', $def_params);
+        $def2->setReturnValue('validate', $output, $def_params);
+        
+        $this->assertIdentical($output,
+            $def->validate($input, $config, $context));
+        
+        $def1->tally();
+        $def2->tally();
+        
+        // third test, all fail, so composite faiils
+        
+        $def1 =& new HTMLPurifier_AttrDefMock($this);
+        $def2 =& new HTMLPurifier_AttrDefMock($this);
+        $defs = array(&$def1, &$def2);
+        $def =& new HTMLPurifier_AttrDef_Composite($defs);
+        $input = 'BOOMA';
+        $output = false;
+        $def_params = array($input, $config, $context);
+        $def1->expectOnce('validate', $def_params);
+        $def1->setReturnValue('validate', false, $def_params);
+        $def2->expectOnce('validate', $def_params);
+        $def2->setReturnValue('validate', false, $def_params);
+        
+        $this->assertIdentical($output,
+            $def->validate($input, $config, $context));
+        
+        $def1->tally();
+        $def2->tally();
+        
+    }
+    
+}
+
+?>
\ No newline at end of file
diff --git a/tests/index.php b/tests/index.php
index dfc1a0f7..cd9d7c5d 100644
--- a/tests/index.php
+++ b/tests/index.php
@@ -64,6 +64,7 @@ $test_files[] = 'AttrDef/LengthTest.php';
 $test_files[] = 'AttrDef/NumberSpanTest.php';
 $test_files[] = 'AttrDef/URITest.php';
 $test_files[] = 'AttrDef/CSSTest.php';
+$test_files[] = 'AttrDef/CompositeTest.php';
 $test_files[] = 'IDAccumulatorTest.php';
 $test_files[] = 'TagTransformTest.php';
 $test_files[] = 'AttrTransform/LangTest.php';