PHP使用VARIABLES创建XML CDATA SECTION

I know there are many examples of creating cdata with php but I have not found one that helps in my situation. I need to create an xml file that will be used by something other than php. I need to create cdata in the xml that will contain a function to be used. The final xml file should look as follows.

    <?xml version="1.0" encoding="utf-8" ?> 
      <component name="Test" extends="out" >
      <script type="text" >
       <![CDATA[
           function init()
           m.content = createObject("RoSGNode","ContentNode")
           m.top.setFocus(true)
          dateNow = CreateObject("roDateTime")
          dateNow = dateNow.asSeconds() - 2000

         addItemName($Iname)
         end function
       ]]>
     </script>
     </component>

Code to create the xml. I just don't know how to create cdata info. Any help would be greatly appreciated.

     $xml=new DOMDocument('1.0', 'UTF-8');
     $xml->preserveWhiteSpace = false;
     $xml->formatOutput = true;
        $components = $xml->createElement("components");
        $name=$xml->createAttribute("name");
        $name->value = "Test";
          $extends=$xml->createAttribute("extends");
          $extends->value = "out";
          $components->appendChild($name);
          $components->appendChild($extends);
             $script = $xml->createElement("script");
             $type=$xml->createAttribute("type");
             $type->value = "text";
             $script->appendChild($type);


        $components->appendChild($script);
    $xml->appendChild($components);
    $xml->save($filename2);

After little more effort, was able to get cdata in.

  $cdata = $xml->createCDATASection("function init()");
  $script->appendChild($cdata);