diff --git a/externs/browser/flash.js b/externs/browser/flash.js
index 5939e82eb29..014f3481af0 100644
--- a/externs/browser/flash.js
+++ b/externs/browser/flash.js
@@ -39,7 +39,7 @@ HTMLObjectElement.prototype.CallFunction = function(xmlString) {};
  * Returns the value of the Flash variable specified by varName or null if the
  * variable does not exist.
  * @param {string} varName The variable name.
- * @return {string?} The variable value.
+ * @return {?string} The variable value.
  */
 HTMLObjectElement.prototype.GetVariable = function(varName) {};
 
diff --git a/externs/browser/gecko_dom.js b/externs/browser/gecko_dom.js
index 3caa9a3d855..b51112ecb93 100644
--- a/externs/browser/gecko_dom.js
+++ b/externs/browser/gecko_dom.js
@@ -340,7 +340,7 @@ Document.prototype.anchors;
  */
 Document.prototype.applets;
 /** @type {boolean} */ Document.prototype.async;
-/** @type {string?} */ Document.prototype.baseURI;
+/** @type {?string} */ Document.prototype.baseURI;
 
 /**
  * @see https://developer.mozilla.org/en/DOM/document.bgColor
diff --git a/externs/browser/w3c_dom1.js b/externs/browser/w3c_dom1.js
index dcebed3d127..13d9f86dba6 100644
--- a/externs/browser/w3c_dom1.js
+++ b/externs/browser/w3c_dom1.js
@@ -618,7 +618,7 @@ Element.prototype.className;
 
 /**
  * @param {string} name
- * @param {number?=} opt_flags
+ * @param {?number=} opt_flags
  * @return {string}
  * @see http://www.w3.org/TR/1998/REC-DOM-Level-1-19981001/level-one-core.html#method-getAttribute
  * @see http://msdn.microsoft.com/en-us/library/ms536429(VS.85).aspx
diff --git a/externs/browser/window.js b/externs/browser/window.js
index 5bf069bd83c..3136c6c4573 100644
--- a/externs/browser/window.js
+++ b/externs/browser/window.js
@@ -134,20 +134,20 @@ function alert(message) {}
 function clearImmediate(immediateID) {}
 
 /**
- * @param {number|undefined?} intervalID
+ * @param {number=} opt_intervalID
  * @see https://developer.mozilla.org/en/DOM/window.clearInterval
  * @suppress {duplicate}
  * @return {undefined}
  */
-function clearInterval(intervalID) {}
+function clearInterval(opt_intervalID) {}
 
 /**
- * @param {number|undefined?} timeoutID
+ * @param {number=} opt_timeoutID
  * @see https://developer.mozilla.org/en/DOM/window.clearTimeout
  * @suppress {duplicate}
  * @return {undefined}
  */
-function clearTimeout(timeoutID) {}
+function clearTimeout(opt_timeoutID) {}
 
 /**
  * @param {*} message