var url = '/captcha/captcheck.php?code=';
        var captchaOK = 2;  // 2 - not yet checked, 1 - correct, 0 - failed
        
        function getHTTPObject()
        {
        try {
        req = new XMLHttpRequest();
          } catch (err1)
          {
          try {
          req = new ActiveXObject("Msxml12.XMLHTTP");
          } catch (err2)
          {
          try {
            req = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (err3)
            {
	req = false;
            }
          }
	}
        return req;
	}
        
        var http = getHTTPObject(); // We create the HTTP Object        
        
        function handleHttpResponse() {
		
        if (http.readyState == 4) {
            captchaOK = http.responseText;
            if(captchaOK != 1) {
              alert('El texto introducido no es valido');
              document.myfrm.txtCaptcha.value='';
              document.myfrm.txtCaptcha.focus();
              return false;
              }
			  
				if (document.myfrm.onsubmit()){
					document.myfrm.submit();
				}
				
              
           }
        }

        function checktxtCaptcha(thecode) {
        http.open("GET", url + escape(thecode), true);
        http.onreadystatechange = handleHttpResponse;
        http.send(null);
        }
        
        function checkform() {
  
        if(document.myfrm.txtCaptcha.value=='') {
          alert('Escribe el texto que ves en la imagen');
          document.myfrm.txtCaptcha.value='';
          document.myfrm.txtCaptcha.focus();
          return false;
          }
          // Now the Ajax CAPTCHA validation
          checktxtCaptcha(document.myfrm.txtCaptcha.value);
          return false;
        }