Når et punkt i Select vælges skal en tekst indsættes i en SPAN

<script type="text/javascript">
var sAX="MSXML2.XMLHTTP.6.0 MSXML2.XMLHTTP.3.0 Msxml2.XMLHTTP Microsoft.XMLHTTP";
(function(){var x=window.XMLHttpRequest;if(!x){var o=s=null,a=sAX.split(" ");for(var i=0,j=a.length;i<j;s=a[i],i++){try{if(o=new ActiveXObject(s))break}catch(e){}}}window.XMLHttpRequest=x?x:o?function(){return new ActiveXObject(s)}:null;o=null;sAX=undefined})();

function foo(oSel, sDisplId) {
    var oDispl = document.getElementById(sDisplId);
    oDispl.firstChild.nodeValue = "Henter data ...";
    var oHttp = new XMLHttpRequest();
    var sQuery = "contxt=getSomething&value=" + encodeURIComponent(oSel.value);
    oHttp.open("post", "/sti/til/fil.asp", true);
    oHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded; charset=utf-8");
    oHttp.onreadystatechange = reqCallback;
    oHttp.send();
   
    function reqCallback() {
        if (oHttp.readyState<4) return;
        eval("var oResp = " + oHttp.responseText);
        if (oResp.error) {
            oDispl.firstChild.nodeValue = "Der opstod en fejl: " + oResp.error;
        }
        else if (oResp.message) {
            oDispl.firstChild.nodeValue = oResp.message;
        }
        oHttp = oResp = null;
    }
}
</script>

<select onchange="foo(this, 'selDisplay')">
    <option value="0">Vælg ...</option>
    <option value="val_A">Option A</option>
    <option value="val_B">Option B</option>
    <option value="val_C">Option C</option>
    <option value="val_D">Option D</option>
</select>
<span id="selDisplay">&nbsp;</span>

{"error":"Hov, der skete dette eller hint"}

{"message":"En eller anden besked til brugeren"}

Response.ContentType = "application/json"
Response.Write "{""message"":""" & minVar & """}"