var popupStatus = 0;
function loadPopup(){ //loads popup only if it is disabled
 if(popupStatus==0){
  $("#popup-bg").css({"opacity": "0.7"});
  $("#popup-bg").fadeIn("slow");
  $("#popup-form").fadeIn("slow");
  popupStatus = 1;
 }
}

function disablePopup(){ //disables popup only if it is enabled
 if(popupStatus==1){
  $("#popup-bg").fadeOut("slow");
  $("#popup-form").fadeOut("slow");
  popupStatus = 0;
 }
}

function centerPopup(){ //request data for centering
 var windowWidth = document.documentElement.clientWidth;
 var windowHeight = document.documentElement.clientHeight;
 var popupHeight = $("#popup-form").height();
 var popupWidth = $("#popup-form").width();
 //centering
 $("#popup-form").css({
  "position": "absolute",
  "top": windowHeight/2-popupHeight/2,
  "left": windowWidth/2-popupWidth/2
 });
 //only need force for IE6	
 $("#popup-bg").css({"height": windowHeight});
}

$(document).ready(function(){	
 //LOADING POPUP
 //Click the button event!
 $("#feedback").click(function(){
  //centering with css
  centerPopup();
  //load popup
  loadPopup();
 });
 
 //CLOSING POPUP
 //Click the x event!
 $("#popup-formClose").click(function(){
  disablePopup();
 });
 //Click out event!
 $("#popup-bg").click(function(){
  disablePopup();
 });
 //Press Escape event!
 $(document).keypress(function(e){
  if(e.keyCode==27 && popupStatus==1){
   disablePopup();
  }
 });
});