function ajax_vote(id) {
        var url = "ajax_vote.php?id="+id+"";
        var poststr = "";
        xmlHttp=GetXmlHttpObject(stateChanged);
        xmlHttp.open("POST", url , true);
        xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
        xmlHttp.setRequestHeader("Content-length", poststr.length);
        xmlHttp.setRequestHeader("Connection", "close");
        xmlHttp.send(poststr)
}

function stateChanged() {
    if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete") {
        updateInnerHtml()
    }
}

function updateInnerHtml() {
   var str = xmlHttp.responseText;
   alert(str);
   if (str=='Your vote has been added!') {
      window.location.reload();      
   }
}

function GetXmlHttpObject(handler) {
    var objXmlHttp=null

    if (navigator.userAgent.indexOf("Opera")>=0) {
        alert("This example doesn't work in Opera")
        return;
    }
    if (navigator.userAgent.indexOf("MSIE")>=0) {
        var strName="Msxml2.XMLHTTP"
        if (navigator.appVersion.indexOf("MSIE 5.5")>=0) {
            strName="Microsoft.XMLHTTP"
        } try {
            objXmlHttp=new ActiveXObject(strName)
            objXmlHttp.onreadystatechange=handler
            return objXmlHttp
        } catch(e) {
            alert("Error. Scripting for ActiveX might be disabled")
            return
        }
    }
    if (navigator.userAgent.indexOf("Mozilla")>=0) {
        objXmlHttp=new XMLHttpRequest()
        objXmlHttp.onload=handler
        objXmlHttp.onerror=handler
        return objXmlHttp
    }
}