var xmlHttp;
     var url;
     var callfn;
     var id;
     
     function DoCallback()
     {
		var dval=document.getElementById("txtCaptcha").value;
		//alert(dval);
     	callfn="show";
     	url="check.php?item="+ dval;
     	xmlsettings(url);     	
     }
     
    function xmlsettings(url)
    {
        xmlHttp=null;
        xmlHttp=GetXmlHttpObject();
        if (xmlHttp==null)
        {
            alert ("Your browser does not support AJAX!");
            return;
        }
        xmlHttp.onreadystatechange=stateChanged;
        xmlHttp.open("GET",url,true);
        xmlHttp.send(null);
    }
    
    function stateChanged() 
    {         
        if (xmlHttp.readyState==4)
        { 
            if(xmlHttp.status==200)		      
	        {
	        	
	            	//alert(xmlHttp.responseText);
	        	
	        	if(callfn=="show")
	            {
	            	document.getElementById("showval").innerHTML=xmlHttp.responseText;
	            	if(xmlHttp.responseText=='Invalid security image.')
	            	document.getElementById("txtCaptcha").value="";
	            }
	            
             }
        }
    }
    
              
   function GetXmlHttpObject()
    {
        var xmlHttp=null;
        try
        {
            // Firefox, Opera 8.0+, Safari
            xmlHttp=new XMLHttpRequest();
        }
        catch (e)
        {
          // Internet Explorer
            try
            {
                //alert("f1");
                xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
            }
            catch (e)
            {
                //alert("f2")
                xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
            }
        }
        return xmlHttp;
    }