// stores the reference to the XMLHttpRequest object
var xmlHttp = createXmlHttpRequestObject(); 

// retrieves the XMLHttpRequest object
function createXmlHttpRequestObject() 
{	
  // will store the reference to the XMLHttpRequest object
  var xmlHttp;
  // if running Internet Explorer
  if(window.ActiveXObject)
  {
    try
    {
      xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    catch (e) 
    {
      xmlHttp = false;
    }
  }
  // if running Mozilla or other browsers
  else
  {
    try 
    {
      xmlHttp = new XMLHttpRequest();
    }
    catch (e) 
    {
      xmlHttp = false;
    }
  }
  // return the created object or display an error message
  if (!xmlHttp)
 
    alert("Error creating the XMLHttpRequest object.");
  else 
    return xmlHttp;
}

// make asynchronous HTTP request using the XMLHttpRequest object 
function podpisatisea()
{
  // proceed only if the xmlHttp object isn't busy
  if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0)
  {
    // retrieve the name typed by the user on the form
    email= encodeURIComponent(document.getElementById("email").value);
    // execute the quickstart.php page from the server
    var now = new Date();
    xmlHttp.open("GET", "en_email.php?email=" + email + "&time=" + now, true);  
    // define the method to handle server responses
    xmlHttp.onreadystatechange = handleServerResponse;
    // make the server request
    xmlHttp.send(null);
  }
  else
  {
     // if the connection is busy, try again after one second  
     alert('The server is busy. Try again');
  }
   
}

// executed automatically when a message is received from the server
function handleServerResponse() 
{
  // move forward only if the transaction has completed
  if (xmlHttp.readyState == 4) 
  {
    // status of 200 indicates the transaction completed successfully
    if (xmlHttp.status == 200) 
    {
      // extract the XML retrieved from the server
      xmlResponse = xmlHttp.responseXML;
      // obtain the document element (the root element) of the XML structure
      xmlDocumentElement = xmlResponse.documentElement;
      // get the text message, which is in the first child of
      // the the document element
      helloMessage = xmlDocumentElement.firstChild.data;
      // update the client display using the data received from the server
	if(helloMessage=='1')
	{
		alert('Email is wrong!');
	}
	if(helloMessage=='2')
	{
		alert('Your email is added to our list.\nThank you for your interest!');
		document.getElementById("email").value='';
	}
	if(helloMessage=='3')
	{
		alert('You email is already present in our database!');
	}
    } 
    // a HTTP status different than 200 signals an error
    else 
    {
      alert("There was a problem accessing the server: " + xmlHttp.statusText);
    }
  }
}

// make asynchronous HTTP request using the XMLHttpRequest object 
function send_message_to_support()
{
  // proceed only if the xmlHttp object isn't busy
  if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0)
  {
    // retrieve the name typed by the user on the form
    email= encodeURIComponent(document.getElementById("sup_email").value);
    phone= encodeURIComponent(document.getElementById("sup_phone").value);
    contn= encodeURIComponent(document.getElementById("sup_contn").value);

    // execute the quickstart.php page from the server
    var now = new Date();
    xmlHttp.open("GET", "en_support.php?sup_email=" + email + "&sup_phone=" + phone + "&sup_contn=" + contn + "&time=" + now, true);  
    // define the method to handle server responses
    xmlHttp.onreadystatechange = SupportResponse;
    // make the server request
    xmlHttp.send(null);
  }
  else
  {
     // if the connection is busy, try again after one second  
     alert('The server is busy. Try again');
  }
}

// executed automatically when a message is received from the server
function SupportResponse() 
{
  // move forward only if the transaction has completed
  if (xmlHttp.readyState == 4) 
  {
    // status of 200 indicates the transaction completed successfully
    if (xmlHttp.status == 200) 
    {
      // extract the XML retrieved from the server
      xmlResponse = xmlHttp.responseXML;
      // obtain the document element (the root element) of the XML structure
      xmlDocumentElement = xmlResponse.documentElement;
      // get the text message, which is in the first child of
      // the the document element
      helloMessage = xmlDocumentElement.firstChild.data;
      // update the client display using the data received from the server
	if(helloMessage=='1')
	{
		alert('Email is wrong!');
	}
	if(helloMessage=='2')
	{
		alert('The phone number is wrong!');
	}
	if(helloMessage=='3')
	{
		alert("You haven't intruduced your question!");
	}
	if(helloMessage=='4')
	{
		alert('Your question is sent to the support service.\nThank you for your interest!');
		document.getElementById("sup_email").value='';
		document.getElementById("sup_phone").value='';
		document.getElementById("sup_contn").value='';
	}
    } 
    // a HTTP status different than 200 signals an error
    else 
    {
      alert("There was a problem accessing the server: " + xmlHttp.statusText);
    }
  }
}

// make asynchronous HTTP request using the XMLHttpRequest object 
function get_calendar(month)
{
  // proceed only if the xmlHttp object isn't busy
  if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0)
  {
    // execute the quickstart.php page from the server
    var now = new Date();
    xmlHttp.open("GET", "en_calendar.php?month=" + month + "&time=" + now, true);  
    // define the method to handle server responses
    xmlHttp.onreadystatechange = SupportCalendar;
    // make the server request
    xmlHttp.send(null);
  }
  else
  {
     // if the connection is busy, try again after one second  
     alert('The server is busy. Try again');
  }
}

// executed automatically when a message is received from the server
function SupportCalendar() 
{
  // move forward only if the transaction has completed
  if (xmlHttp.readyState == 4) 
  {
    // status of 200 indicates the transaction completed successfully
    if (xmlHttp.status == 200) 
    {
      // extract the XML retrieved from the server
      TextResponse = xmlHttp.responseText;
      calendar.innerHTML=TextResponse;
      
    } 
    // a HTTP status different than 200 signals an error
    else 
    {
      alert("There was a problem accessing the server: " + xmlHttp.statusText);
    }
  }
}