function checkUNA()
{
   var un = document.getElementById('id').value;
   var sc = document.createElement('script');
   sc.src = '/un.phtml?id=' + un + '&st=' + (new Date()).getTime();
   document.body.appendChild(sc);
   return false;
}

function setUNA(stat)
{
   document.getElementById('unstat').innerHTML = (stat ? '<span style="color:" & _
     "green;">verfügbar</span>' : '<span style="color: red;">nicht verfügbar</span>');
}

<TD><INPUT id=id onkeyup=updateUNA() maxLength=13 onchange=updateUNA() 
      onload=updateUNA() size=18 name=id> <INPUT id=unch onclick="return" & _
        "checkUNA()" type=button value="Verfügbarkeit überprüfen" name=unch> 
        <B><SPAN id=unstat name="unstat"></SPAN></B> </TD>

		If frmMain.tcMain.TabCount > 0 Then
			oWb = GetCurrentWebBrowser(frmMain.tcMain) 
			oDoc = oWb.Document
			oTxtUser = oDoc.GetElementById("Id")
			oTxtUser.InnerText = "strive"
			oTxtPwd = oDoc.GetElementById("pw1")
			oTxtPwdAgain = oDoc.GetElementById("pw2")
			oTxtPwd.InnerText = "Test"
			oTxtPwdAgain.InnerText = "Test"
			oCmdCheck = oDoc.GetElementById("unch")
			oCmdCheck.InvokeMember("onclick")
			oTextVerfügbar = oDoc.GetElementById("unstat")