diff --git a/functions/http.xml b/functions/http.xml
index 105b24c392..e801bc6ad8 100644
--- a/functions/http.xml
+++ b/functions/http.xml
@@ -121,11 +121,11 @@ header ("Pragma: no-cache");                          // HTTP/1.0
      <funcprototype>
       <funcdef>int <function>setcookie</function></funcdef>
       <paramdef>string <parameter>name</parameter></paramdef>
-      <paramdef>string <parameter>value</parameter></paramdef>
-      <paramdef>int <parameter>expire</parameter></paramdef>
-      <paramdef>string <parameter>path</parameter></paramdef>
-      <paramdef>string <parameter>domain</parameter></paramdef>
-      <paramdef>int <parameter>secure</parameter></paramdef>
+      <paramdef>string <parameter><optional>value</optional></parameter></paramdef>
+      <paramdef>int <parameter><optional>expire</optional></parameter></paramdef>
+      <paramdef>string <parameter><optional>path</optional></parameter></paramdef>
+      <paramdef>string <parameter><optional>domain</optional></parameter></paramdef>
+      <paramdef>int <parameter><optional>secure</optional></parameter></paramdef>
      </funcprototype>
     </funcsynopsis>
     <para>
@@ -152,13 +152,22 @@ header ("Pragma: no-cache");                          // HTTP/1.0
      <parameter>secure</parameter> indicates that the cookie should
      only be transmitted over a secure HTTPS connection.
     </para>
-    <para>  
+    <para>
      Common Pitfalls:
+     <itemizedlist>
+      <listitem>
+       <simpara>
+        Cookies will not become visible until the next loading of a page that 
+        the cookie should be visible for.
+       </simpara>
+      </listitem>
+      <listitem>
+       <simpara>
+        Cookies must be deleted with the same parameters as they were set with.
+       </simpara>
+      </listitem>
+     </itemizedlist>
     </para>
-    <simpara>
-     Cookies will not become visible until the next loading of a page that 
-     the cookie should be visible for.
-    </simpara> 
     <simpara>
      In PHP3, multiple calls to <function>setcookie</function> in the same
      script will be performed in reverse order. If you are trying to
@@ -167,9 +176,9 @@ header ("Pragma: no-cache");                          // HTTP/1.0
      <function>setcookie</function> are performed in the order called.
     </simpara>
     <para>
-     Some examples follow:
+     Some examples follow how to send cookies:
      <example>
-      <title><function>setcookie</function> examples</title>
+      <title><function>setcookie</function> send examples</title>
       <programlisting role="php">
 setcookie ("TestCookie", "Test Value");
 setcookie ("TestCookie", $value,time()+3600);  /* expire in 1 hour */
@@ -177,6 +186,17 @@ setcookie ("TestCookie", $value,time()+3600, "/~rasmus/", ".utoronto.ca", 1);
       </programlisting>
      </example>
     </para>
+    <para>
+     Examples follow how to delete cookies send in previous example:
+     <example>
+      <title><function>setcookie</function> delete examples</title>
+      <programlisting role="php">
+setcookie ("TestCookie");
+setcookie ("TestCookie", "",time());
+setcookie ("TestCookie", "",time(), "/~rasmus/", ".utoronto.ca", 1);
+      </programlisting>
+     </example>
+    </para>
     <para>
      Note that the value portion of the cookie will automatically be
      urlencoded when you send the cookie, and when it is received, it