diff --git a/library/HTMLPurifier/AttrDef/Integer.php b/library/HTMLPurifier/AttrDef/Integer.php
index 71ac98c3..d6953d61 100644
--- a/library/HTMLPurifier/AttrDef/Integer.php
+++ b/library/HTMLPurifier/AttrDef/Integer.php
@@ -13,15 +13,31 @@ class HTMLPurifier_AttrDef_Integer extends HTMLPurifier_AttrDef
 {
     
     /**
-     * Bool indicating whether or not integers can only be positive.
+     * Bool indicating whether or not negative values are allowed
      */
-    var $non_negative = false;
+    var $negative = true;
     
     /**
-     * @param $non_negative bool indicating whether or not only positive
+     * Bool indicating whether or not zero is allowed
      */
-    function HTMLPurifier_AttrDef_Integer($non_negative = false) {
-        $this->non_negative = $non_negative;
+    var $zero = true;
+    
+    /**
+     * Bool indicating whether or not positive values are allowed
+     */
+    var $positive = true;
+    
+    /**
+     * @param $negative Bool indicating whether or not negative values are allowed
+     * @param $zero Bool indicating whether or not zero is allowed
+     * @param $positive Bool indicating whether or not positive values are allowed
+     */
+    function HTMLPurifier_AttrDef_Integer(
+        $negative = true, $zero = true, $positive = true
+    ) {
+        $this->negative = $negative;
+        $this->zero     = $zero;
+        $this->positive = $positive;
     }
     
     function validate($integer, $config, &$context) {
@@ -29,15 +45,27 @@ class HTMLPurifier_AttrDef_Integer extends HTMLPurifier_AttrDef
         $integer = $this->parseCDATA($integer);
         if ($integer === '') return false;
         
-        if ( !$this->non_negative && $integer[0] === '-' ) {
+        // we could possibly simply typecast it to integer, but there are
+        // certain fringe cases that must not return an integer.
+        
+        // clip leading sign
+        if ( $this->negative && $integer[0] === '-' ) {
             $digits = substr($integer, 1);
-        } elseif( $integer[0] === '+' ) {
-            $digits = $integer = substr($integer, 1);
+            if ($digits === '0') $integer = '0'; // rm minus sign for zero
+        } elseif( $this->positive && $integer[0] === '+' ) {
+            $digits = $integer = substr($integer, 1); // rm unnecessary plus
         } else {
             $digits = $integer;
         }
         
+        // test if it's numeric
         if (!ctype_digit($digits)) return false;
+        
+        // perform scope tests
+        if (!$this->zero     && $integer == 0) return false;
+        if (!$this->positive && $integer > 0) return false;
+        if (!$this->negative && $integer < 0) return false;
+        
         return $integer;
         
     }
diff --git a/library/HTMLPurifier/HTMLDefinition.php b/library/HTMLPurifier/HTMLDefinition.php
index 374eea07..709663e4 100644
--- a/library/HTMLPurifier/HTMLDefinition.php
+++ b/library/HTMLPurifier/HTMLDefinition.php
@@ -331,7 +331,7 @@ class HTMLPurifier_HTMLDefinition
         $this->info['col']->attr['width'] =
         $this->info['colgroup']->attr['width'] = $e_MultiLength;
         
-        $e__NumberSpan = new HTMLPurifier_AttrDef_Integer(true);
+        $e__NumberSpan = new HTMLPurifier_AttrDef_Integer(false, false, true);
         $this->info['colgroup']->attr['span'] =
         $this->info['col']->attr['span']   =
         $this->info['td']->attr['rowspan'] =
diff --git a/tests/HTMLPurifier/AttrDef/IntegerTest.php b/tests/HTMLPurifier/AttrDef/IntegerTest.php
index 00d5831c..20d71689 100644
--- a/tests/HTMLPurifier/AttrDef/IntegerTest.php
+++ b/tests/HTMLPurifier/AttrDef/IntegerTest.php
@@ -16,20 +16,45 @@ class HTMLPurifier_AttrDef_IntegerTest extends HTMLPurifier_AttrDefHarness
         $this->assertDef('14');
         $this->assertDef('+24', '24');
         $this->assertDef(' 14 ', '14');
+        $this->assertDef('-0', '0');
         
         $this->assertDef('-1.4', false);
         $this->assertDef('3.4', false);
-        $this->assertDef('asdf', false);
+        $this->assertDef('asdf', false); // must not return zero
+        $this->assertDef('2in', false); // must not return zero
         
     }
     
-    function testNonNegative() {
+    function assertRange($negative, $zero, $positive) {
+        $this->assertDef('-100', $negative);
+        $this->assertDef('-1', $negative);
+        $this->assertDef('0', $zero);
+        $this->assertDef('1', $positive);
+        $this->assertDef('42', $positive);
+    }
+    
+    function testRange() {
         
-        $this->def = new HTMLPurifier_AttrDef_Integer(true);
+        $this->def = new HTMLPurifier_AttrDef_Integer(false);
+        $this->assertRange(false, true, true); // non-negative
         
-        $this->assertDef('0');
-        $this->assertDef('1');
-        $this->assertDef('-1', false);
+        $this->def = new HTMLPurifier_AttrDef_Integer(false, false);
+        $this->assertRange(false, false, true); // positive
+        
+        
+        // fringe cases
+        
+        $this->def = new HTMLPurifier_AttrDef_Integer(false, false, false);
+        $this->assertRange(false, false, false); // allow none
+        
+        $this->def = new HTMLPurifier_AttrDef_Integer(true, false, false);
+        $this->assertRange(true, false, false); // negative
+        
+        $this->def = new HTMLPurifier_AttrDef_Integer(false, true, false);
+        $this->assertRange(false, true, false); // zero
+        
+        $this->def = new HTMLPurifier_AttrDef_Integer(true, true, false);
+        $this->assertRange(true, true, false); // non-positive
         
     }
     
diff --git a/tests/HTMLPurifier/Strategy/ValidateAttributesTest.php b/tests/HTMLPurifier/Strategy/ValidateAttributesTest.php
index 6e610fb7..82f87607 100644
--- a/tests/HTMLPurifier/Strategy/ValidateAttributesTest.php
+++ b/tests/HTMLPurifier/Strategy/ValidateAttributesTest.php
@@ -120,6 +120,10 @@ class HTMLPurifier_Strategy_ValidateAttributesTest extends
         $inputs[21] = '<span dir="blahblah">Invalid value!</span>';
         $expect[21] = '<span>Invalid value!</span>';
         
+        // test col.span is non-zero
+        $inputs[22] = '<col span="0" />';
+        $expect[22] = '<col />';
+        
         $this->assertStrategyWorks($strategy, $inputs, $expect, $config);
         
     }