// JavaScript Document

var http = false;

if(navigator.appName == "Microsoft Internet Explorer") {
  http = new ActiveXObject("Microsoft.XMLHTTP");
} else {
  http = new XMLHttpRequest();
} 

function replaceground() {
  http.open("GET", "venue-ground.php", true);
  http.onreadystatechange=function() {
    if(http.readyState == 4) {
      document.getElementById('mainContent').innerHTML = http.responseText;
    }
  }
  http.send(null);  
  document.getElementById('hologram').style.visibility = "hidden"; 
  
}

function replacemiddle() {
  http.open("GET", "venue-middle.php", true);
  http.onreadystatechange=function() {
    if(http.readyState == 4) {
      document.getElementById('mainContent').innerHTML = http.responseText;
    }
  }
  http.send(null);  
  document.getElementById('hologram').style.visibility = "hidden"; 
}

function replacetop() {
  http.open("GET", "venue-top.php", true);
  http.onreadystatechange=function() {
    if(http.readyState == 4) {
      document.getElementById('mainContent').innerHTML = http.responseText;
    }
  }
  http.send(null);
  document.getElementById('hologram').style.visibility = "visible"; 
}