diff --git a/CHANGELOG b/CHANGELOG
index bd3235c..f3e18b8 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Make setStyle() with opacity: 0 in Internet Explorer work correctly.  [Thomas Fuchs]
+
 * Form.Element.activate shouldn't raise an exception when the form or field is hidden.  [sam]
 
 * Remove support for "throw $continue" in Enumerable.  Use "return" instead.  [sam]
diff --git a/src/dom.js b/src/dom.js
index c55a2df..c8332bb 100644
--- a/src/dom.js
+++ b/src/dom.js
@@ -333,7 +333,7 @@ Element.Methods = {
             !/Konqueror|Safari|KHTML/.test(navigator.userAgent)) ? 0.999999 : 1.0;
           if(/MSIE/.test(navigator.userAgent) && !window.opera)
             element.style.filter = element.getStyle('filter').replace(/alpha\([^\)]*\)/gi,'');
-        } else if(value == '') {
+        } else if(value === '') {
           if(/MSIE/.test(navigator.userAgent) && !window.opera)
             element.style.filter = element.getStyle('filter').replace(/alpha\([^\)]*\)/gi,'');
         } else {
diff --git a/test/unit/dom.html b/test/unit/dom.html
index 5c73682..4850e09 100644
--- a/test/unit/dom.html
+++ b/test/unit/dom.html
@@ -610,9 +610,11 @@
       $('style_test_3').setStyle({ opacity: 0.5 });
       assertEqual(0.5, $('style_test_3').getStyle('opacity'));
       
-      // should remove opacity
       $('style_test_3').setStyle({ opacity: '' });
       assertEqual(1, $('style_test_3').getStyle('opacity'));
+      
+      $('style_test_3').setStyle({ opacity: 0 });
+      assertEqual(0, $('style_test_3').getStyle('opacity'));
     }},
     
     testElementGetStyle: function() { with(this) {