function show_layer() {
  
    var mainTab = document.body.getElementsByTagName("table")[3];
    var subTab1 = mainTab.getElementsByTagName("td")[4];
    var subTab2 = subTab1.getElementsByTagName("table")[3];
    var offsetLeft = mainTab.offsetLeft + subTab1.offsetLeft + subTab2.offsetLeft;
    var offsetTop = mainTab.offsetTop + subTab1.offsetTop + subTab2.offsetTop;
    var layer = document.createElement("div");
    var br = document.createElement("br");
    var button = document.createElement("input");
    var txt = document.createTextNode("You have been registered successfully");
    var p1 = document.createElement("p");
    var p2 = document.createElement("p");

    layer.setAttribute("class", "navigation");
    layer.setAttribute("id", "navigation");
    p1.setAttribute("id", "navigation");
    button.setAttribute("type", "button");
    button.setAttribute("class", "button");
    button.setAttribute("value", "close");
    button.setAttribute("onclick", "hide_layer()");
    layer.appendChild(txt);
    layer.style.width = subTab2.offsetWidth-20;
    layer.style.height = subTab2.offsetHeight-20;
    layer.style.left = offsetLeft;
    layer.style.top = offsetTop;
    layer.appendChild(p1);
    p2.style.top = 600;
    p2.appendChild(button);
    layer.appendChild(p2);
    document.body.appendChild(layer);
}

function hide_layer() {

   var layer = document.getElementById("navigation");
   layer.style.visibility = "hidden";
}