function createRequestObject() {
        var ro;
        try {
                if (window.XMLHttpRequest) ro = new XMLHttpRequest()
                else ro = new ActiveXObject("Microsoft.XMLHTTP");
        }
        catch(er) {
            alert(er.description);
        }
        return ro;
}
var http = createRequestObject();

function handleDrugResponse() {
    if(http.readyState == 4){
        var response = http.responseText;
            changeText("fdiv", response)
        }
}

function changeText( div2show, text ) {
            var viewer = document.getElementById(div2show);
        viewer.innerHTML=text
}
function doAction(){

        var nm = document.getElementById("secret");
   if (nm.value=="drug"){
    sdrug = document.getElementById(nm.value);
    http.open('get', '/modules/virtualtest.php?drug='+sdrug.options[sdrug.selectedIndex].value);
   }
   if (nm.value=="frequency" || nm.value=="lasttime" || nm.value=="bodytype"){
    freq = document.getElementsByName(nm.value);
    var sel ="";
    for (i=0; i<freq.length; i++){
        if (freq[i].checked) sel=freq[i];
    }
    http.open('get', '/modules/virtualtest.php?'+nm.value+'='+sel.value);
   }
   if (nm.value=="lasttime"){
    var btn = document.getElementById("btnnxt");
        btn.value="Start test again";
        //btn.style.visibility="hidden"; 
   }
    http.onreadystatechange = handleDrugResponse;
    http.send(null);
   return false;
}