http://scrap.php.xdomain.jp/javascript_screen_lock/#i-2
<html> <head> <script> // ロック用関数 function screenLock(){ // ロック用のdivを生成 var div = document.createElement("div"); div.style.position = "fixed"; div.style.left = "0px"; div.style.top = "0px"; div.style.width = "100%"; div.style.height = "100%"; div.style.zIndex = "9999"; div.style.backgroundColor = "black"; div.style.opacity = 0.8; div.style.textAlign = "center"; div.innerHTML = "<h5 style='color:white;'>アップロード中</h5><img src='loading.gif'>"; var objBody = document.querySelector("body"); objBody.appendChild(div); setTimeout( function() { div.remove(); }, 3000 ); } </script> </head> <body> <h1>Javascriptで画面ロックする</h1> <button onclick="screenLock()">ScreenLock</button> </body> </html>