Javascript: Check if iframe is loaded

var iframe = document.createElement("iframe");
iframe.src = "http://notepad2.blogspot.com/";

if (iframe.attachEvent){
   iframe.attachEvent("onload", function(){
       alert("Local iframe is now loaded.");
   });
} else {
   iframe.onload = function(){
       alert("Local iframe is now loaded.");
   };
}

document.body.appendChild(iframe);

See Also: iframe, onload and document.domain