The perfect way to determine whether an iframe is loaded_javascript skills

Copy code The code is as follows:

var iframe = document.createElement("iframe");
iframe.src = "http://www.jb51.net";

if (!/*@cc_on!@*/0) { //if not IE
iframe.onload = function( ){
alert("Local iframe is now loaded.");
};
} else {
iframe.onreadystatechange = function(){
if (iframe.readyState == " complete"){
alert("Local iframe is now loaded.");
}
};
}
document.body.appendChild(iframe);

Recently, Christopher provided a comment on Nicholas C. Zakas article "Iframes, onload, and document.domain" A new judgment method (perfect):

Copy code The code is as follows:

var iframe = document.createElement("iframe");
iframe.src = "http://www.jb51.net";

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);

Click for additional explanation:

IE supports iframe's onload event , but it is invisible and needs to be registered through attachEvent.
The second method is more perfect than the first method because the readystatechange event has some potential problems compared to the load event.