function showUser(str)
{
    
    if (str=="")
    {
        document.getElementById("txtHint").innerHTML="";
        return;
    }
    
    
    
    if (window.XMLHttpRequest)
    {// code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp=new XMLHttpRequest();
    }
    else
    {// code for IE6, IE5
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
    }
    xmlhttp.onreadystatechange=function()
    {
        if (xmlhttp.readyState==4 && xmlhttp.status==200)
        {
            document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
        }
    }
 
    xmlhttp.open("POST","/q_table",true);
    
                
    xmlhttp.send("FirstName=1");
}

        <div id="txtHint">

        </div>
        <input type="submit" id="CreateRecordc" onclick="showUser('1')" value="CheckConnect1" />

String _test  = (String) request.getParameter("FirstName");