是否有客户端方式来检测X-Frame-Options？

Question

Is there any good way to detect when a page isn't going to display in a frame because of the X-Frame-Options header? I know I can request the page serverside and look for the header, but I was curious if the browser has any mechanism for catching this error.

Answer 1

OK, this one is old but still relevant.

Fact: When an iframe loads a url which is blocked by a X-Frame-Options the loading time is very short.

Hack: So if the onload occurs immediately I know it's probably a X-Frame-Options issue.

Disclaimer: This is probably one of the 'hackiest' code I've written, so don't expect much:

var timepast=false; 
var iframe = document.createElement("iframe");

iframe.style.cssText = "position:fixed; top:0px; left:0px; bottom:0px; right:0px; width:100%; height:100%; border:none; margin:0; padding:0; overflow:hidden; z-index:999999;";
iframe.src = "http://pix.do"; // This will work
//iframe.src = "http://google.com"; // This won't work
iframe.id = "theFrame";

// If more then 500ms past that means a page is loading inside the iFrame
setTimeout(function() {
    timepast = true;
},500);

if (iframe.attachEvent){
    iframe.attachEvent("onload", function(){
    if(timepast) {
            console.log("It's PROBABLY OK");
        }
        else {
            console.log("It's PROBABLY NOT OK");
        }
    });
} 
else {
    iframe.onload = function(){
        if(timepast) {
            console.log("It's PROBABLY OK");
        }
        else {
            console.log("It's PROBABLY NOT OK");
        }
    };
}
document.body.appendChild(iframe);

Answer 2

Disclaimer: this answer I wrote in 2012(Chrome was version ~20 at that time) is outdated and I'll keep it here for historical purposes only. Read and use at your own risk.

---

Ok, this is a bit old question, but here's what I found out (it's not a complete answer) for Chrome/Chromium.

the way do detect if a frame pointing to a foreign address has loaded is simply to try to access its contentWindow or document.

here's the code I used:

element.innerHTML = '<iframe class="innerPopupIframe" width="100%" height="100%" src="'+href+'"></iframe>';
myframe = $(element).find('iframe');

then, later:

try {
    var letstrythis = myframe.contentWindow;
} catch(ex) {
    alert('the frame has surely started loading');
}

the fact is, if the X-Frame-Options forbid access, then myFrame.contentWindow will be accessible.

the problem here is what I called "then, later". I haven't figured out yet on what to rely, which event to subsribe to find when is the good time to perform the test.

Answer 3

This is based on @Iftach 's answer, but is a slightly less hacky.

It checks to see if iframe.contentWindow.length > 0 which would suggest that the iframe has successfully loaded.

Additionally, it checks to see if the iframe onload event has fired within 5s and alerts that too. This catches failed loading of mixed content (in an albeit hacky manner).

var iframeLoaded = false;
var iframe = document.createElement('iframe');

// ***** SWAP THE `iframe.src` VALUE BELOW FOR DIFFERENT RESULTS ***** //
// iframe.src = "https://davidsimpson.me"; // This will work
iframe.src = "https://google.com"; // This won't work

iframe.id = 'theFrame';
iframe.style.cssText = 'position:fixed; top:40px; left:10px; bottom:10px;'
 + 'right:10px; width:100%; height:100%; border:none; margin:0; padding:0; overflow:hidden; z-index:999999;';

var iframeOnloadEvent = function () {
    iframeLoaded = true;
  var consoleDiv = document.getElementById('console');
    if (iframe.contentWindow.length > 0) {
    consoleDiv.innerHTML = '✔ Content window loaded: ' + iframe.src;
    consoleDiv.style.cssText = 'color: green;'
    } else {
    consoleDiv.innerHTML = '✘ Content window failed to load: ' + iframe.src;
    consoleDiv.style.cssText = 'color: red;'
    }
} 

if (iframe.attachEvent){
    iframe.attachEvent('onload', iframeOnloadEvent);
} else {
    iframe.onload = iframeOnloadEvent;
}
document.body.appendChild(iframe);

// iframe.onload event doesn't trigger in firefox if loading mixed content (http iframe in https parent) and it is blocked.
setTimeout(function () {
    if (iframeLoaded === false) {
        console.error('%c✘ iframe failed to load within 5s', 'font-size: 2em;');
    consoleDiv.innerHTML = '✘ iframe failed to load within 5s: ' + iframe.src;
    consoleDiv.style.cssText = 'color: red;'    
  }
}, 5000);

Live demo here - https://jsfiddle.net/dvdsmpsn/7qusz4q3/ - so you can test it in the relevant browsers.

At time of writing, it works on the current version on Chrome, Safari, Opera, Firefox, Vivaldi & Internet Explorer 11. I've not tested it in other browsers.

Answer 4

Online test tools might be useful. I used https://www.hurl.it/ . you can clearly see the response header. Look for X-frame-option. if value is deny - It will not display in iframe. same origin- only from the same domain, allow- will allow from specific websites.

If you want to try another tool, you can simply google for 'http request test online'.

Answer 5

The only thing I can think of is to proxy an AJAX request for the url, then look at the headers, and if it doesn't have X-Frame-Options, then show it in the iframe. Far from ideal, but better than nothing.

Answer 6

At least in Chrome, you can notice the failure to load because the iframe.onload event doesn't trigger. You could use that as an indicator that the page might not allow iframing.

Answer 7

This can be achieved through

a) Create a new IFrame through CreateElement

b) Set its display as 'none'

c) Load the URL through the src attribute

d) In order to wait for the iframe to load, use the SetTimeOut method to delay a function call (i had delayed the call by 10 sec)

e) In that function, check for the ContentWindow length.

f) if the length > 0, then the url is loaded else URL is not loaded due to X-Frame-Options

Below is the sample code:

function isLoaded(val) {
var elemId = document.getElementById('ctlx');
if (elemId != null)
    document.body.removeChild(elemId);


var obj= document.createElement('iframe');

obj.setAttribute("id", "ctlx");

obj.src = val;
obj.style.display = 'none';

document.body.appendChild(obj);

setTimeout(canLoad, 10000);  

}

function canLoad() {
//var elemId = document.getElementById('ctl100');
var elemId = document.getElementById('ctlx');
if (elemId.contentWindow.length > 0) {
    elemId.style.display = 'inline';

}

else {
    elemId.src = '';
    elemId.style.display = 'none';
    alert('not supported');
}
}

Answer 8

This is how I had checked for X-Frames-Options for one of my requirements. On load of a JSP page, you can use AJAX to send an asynchronous request to the specific URL as follows:

var request = new XMLHttpRequest();
request.open('GET', <insert_URL_here>, false);
request.send(null);

After this is done, you can read the response headers received as follows:

var headers = request.getAllResponseHeaders();

You can then iterate over this to find out the value of the X-Frames-Options. Once you have the value, you can use it in an appropriate logic.