var appName = location.pathname.split('/')[1];

var oLoadImg = new Image();
oLoadImg.src = "/" + appName + "/App_Themes/Airnostrum/images/gif-cargando2.gif";

document.write("<div style='width:200px; height:100px; position:absolute; left:50%; top:50%; margin-top:-95px; margin-left:-130px' id='loading'><IMG SRC='" + oLoadImg.src + "'/></div>");

function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

addLoadEvent(function() {
  document.getElementById("loading").style.display="none";
});