diff --git a/TODO.txt b/TODO.txt
index da98e6f6..b6d4c7eb 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,15 +1,13 @@
 Todo List
 
-Primary:
- - (In Progress) Implement attribute validation
- - Implement HTMLPurifier (trivial)
-
 Code issues:
- - Rename AbstractTest to Harness
  - (?) Create a TokenFactory to prevent really long lines
  - Massive profiling
  - Fix IPv6 issues
- - Make URI validation routines tighter
+ - Make URI validation routines tighter (especially mailto)
+ - Distinguish between different types of URIs, for instance, a mailto URI
+   in IMG SRC is nonsensical
+ - Factor out Host validation to its own AttrDef
 
 Enhancements:
  - Do fixes for Firefox's inability to handle COL alignment props (Bug 915)
diff --git a/docs/progress.html b/docs/progress.html
index ccca4487..06913f68 100644
--- a/docs/progress.html
+++ b/docs/progress.html
@@ -71,7 +71,7 @@ thead th {text-align:left;padding:0.1em;background-color:#EEE;}
 <tr><td>scope</td><td>TD, TH</td><td>W3C only: No browser implementation</td></tr>
 </tbody>
 
-<tbody>
+<tbody class="impl-yes">
 <tr><th colspan="3">URI</th></tr>
 <tr><td rowspan="2">cite</td><td>BLOCKQUOTE, Q</td><td>-</td></tr>
     <tr><td>DEL, INS</td><td>-</td></tr>
@@ -103,6 +103,7 @@ thead th {text-align:left;padding:0.1em;background-color:#EEE;}
 <tr><td>noshade</td><td>HR</td><td>Boolean, style 'border-style:solid;'</td></tr>
 <tr><td>nowrap</td><td>TD, TH</td><td>Boolean, style 'white-space:nowrap;' (not compat with IE5)</td></tr>
 <tr><td>size</td><td>HR</td><td>Near-equiv 'width', needs px suffix if original was pixels</td></tr>
+<tr><td>src</td><td>IMG</td><td>Required, insert blank or default img if not set</td></tr>
 <tr><td>start</td><td>OL</td><td>Poorly supported 'counter-reset', transform may not be desirable</td></tr>
 <tr><td rowspan="3">type</td><td>LI</td><td rowspan="3">Equivalent style 'list-style-type', different allowed values though. (needs testing)</td></tr>
     <tr><td>OL</td></tr>
diff --git a/library/HTMLPurifier/Definition.php b/library/HTMLPurifier/Definition.php
index b76b270c..418f04c7 100644
--- a/library/HTMLPurifier/Definition.php
+++ b/library/HTMLPurifier/Definition.php
@@ -10,6 +10,7 @@ require_once 'HTMLPurifier/AttrDef.php';
     require_once 'HTMLPurifier/AttrDef/Length.php';
     require_once 'HTMLPurifier/AttrDef/MultiLength.php';
     require_once 'HTMLPurifier/AttrDef/NumberSpan.php';
+    require_once 'HTMLPurifier/AttrDef/URI.php';
 require_once 'HTMLPurifier/AttrTransform.php';
     require_once 'HTMLPurifier/AttrTransform/Lang.php';
     require_once 'HTMLPurifier/AttrTransform/TextAlign.php';
@@ -310,6 +311,14 @@ class HTMLPurifier_Definition
         $this->info['td']->attr['colspan'] =
         $this->info['th']->attr['colspan'] = $e__NumberSpan;
         
+        $e_URI = new HTMLPurifier_AttrDef_URI();
+        $this->info['a']->attr['href'] =
+        $this->info['img']->attr['longdesc'] =
+        $this->info['img']->attr['src'] =
+        $this->info['del']->attr['cite'] =
+        $this->info['ins']->attr['cite'] =
+        $this->info['blockquote']->attr['cite'] =
+        $this->info['q']->attr['cite'] = $e_URI;
         
         //////////////////////////////////////////////////////////////////////
         // UNIMP : info_tag_transform : transformations of tags
diff --git a/tests/HTMLPurifier/Strategy/ValidateAttributesTest.php b/tests/HTMLPurifier/Strategy/ValidateAttributesTest.php
index 69873e30..ff1488f4 100644
--- a/tests/HTMLPurifier/Strategy/ValidateAttributesTest.php
+++ b/tests/HTMLPurifier/Strategy/ValidateAttributesTest.php
@@ -87,6 +87,14 @@ class HTMLPurifier_Strategy_ValidateAttributesTest extends
 HTML;
         $expect[13] = $inputs[13];
         
+        // test URI
+        $inputs[14] = '<a href="http://www.google.com/">Google</a>';
+        $expect[14] = $inputs[14];
+        
+        // test invalid URI
+        $inputs[15] = '<a href="javascript:badstuff();">Google</a>';
+        $expect[15] = '<a>Google</a>';
+        
         $this->assertStrategyWorks($strategy, $inputs, $expect, $config);
         
     }