Getting a single xml node with javascript

This should be really simple but for some reason I can't seem to get it to work; So I have a XML file as follows:

<board>
     <version>1</version>
<r>
    <c>
        <tile>g</tile>
    </c>

    <c>
        <tile>B</tile>
    </c>
</r>

<r>
    <c>
        <tile>C</tile>
    </c>

    <c>
        <tile>D</tile>
    </c>
</r>
</board>

And some JavaScript like:开发者_开发百科

    function get_cversion(){
    if (window.XMLHttpRequest) { 
        xmlhttp = new XMLHttpRequest(); 
    } 
    else { 
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); 
    } 
    xmlhttp.open("GET", "board.XML", false); 
    xmlhttp.send(); 
    xmlDoc = xmlhttp.responseXML;
    var mytext = 0


    var x=xmlDoc.getElementsByTagName("version");
    mytext = (x[0].childNodes[0].nodeValue);
    mytext += "";
    document.frmOne.input1.value = ""+mytext;
}

and last, I have a form on the page like this:

<FORM NAME = frmOne>

    1val: <INPUT TYPE = Text NAME = input1 SIZE = 4 value ="">
    <p>
    <Input Type = Button NAME = b1 VALUE = "Save val" onClick = update_XX()>
    <p> 
    <Input Type = Button NAME = b2 VALUE = "WOOOOO" onClick = get_cversion()>
</FORM>

I'm still really new at this whole XML game. I know I must be missing something really obvious but I just cant see it, any help would be greatly appreciated.

Thanks.

---

You might want to check the status of the request before processing the XML. Your code should look something like this,

    function get_cversion(){
    if (window.XMLHttpRequest) { 
        xmlhttp = new XMLHttpRequest(); 
    } 
    else { 
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); 
    } 
    xmlhttp.open("GET", "board.XML", false); 
    xmlhttp.send();                   
         if(xmlhttp.status == 200) {
          var xmlDoc = xmlhttp.responseXML;
          var mytext = 0       
          var x=xmlDoc.getElementsByTagName("version");
          mytext = (x[0].childNodes[0].nodeValue);
          mytext += "";
          document.frmOne.input1.value = ""+mytext;            
      }
}