Well there is 2 ways to change the location.href
. Either you can write location.href = "y.html"
, which reloads the page or can use the history API which does not reload the page. I experimented with the first a lot recently.
If you open a child window and capture the load of the child page from the parent window, then different browsers behave very differently. The only thing that is common, that they remove the old document and add a new one, so for example adding readystatechange or load event handlers to the old document does not have any effect. Most of the browsers remove the event handlers from the window object too, the only exception is Firefox. In Chrome with Karma runner and in Firefox you can capture the new document in the loading readyState if you use unload + next tick
. So you can add for example a load event handler or a readystatechange event handler or just log that the browser is loading a page with a new URI. In Chrome with manual testing (probably GreaseMonkey too) and in Opera, PhantomJS, IE10, IE11 you cannot capture the new document in the loading state. In those browsers the unload + next tick
calls the callback a few hundred msecs later than the load event of the page fires. The delay is typically 100 to 300 msecs, but opera simetime makes a 750 msec delay for next tick, which is scary. So if you want a consistent result in all browsers, then you do what you want to after the load event, but there is no guarantee the location won't be overridden before that.
var uuid = "win." + Math.random();
var timeOrigin = new Date();
var win = window.open("about:blank", uuid, "menubar=yes,location=yes,resizable=yes,scrollbars=yes,status=yes");
var callBacks = [];
var uglyHax = function (){
var done = function (){
uglyHax();
callBacks.forEach(function (cb){
cb();
});
};
win.addEventListener("unload", function unloadListener(){
win.removeEventListener("unload", unloadListener); // Firefox remembers, other browsers don't
setTimeout(function (){
// IE10, IE11, Opera, PhantomJS, Chrome has a complete new document at this point
// Chrome on Karma, Firefox has a loading new document at this point
win.document.readyState; // IE10 and IE11 sometimes fails if I don't access it twice, idk. how or why
if (win.document.readyState === "complete")
done();
else
win.addEventListener("load", function (){
setTimeout(done, 0);
});
}, 0);
});
};
uglyHax();
callBacks.push(function (){
console.log("cb", win.location.href, win.document.readyState);
if (win.location.href !== "http://localhost:4444/y.html")
win.location.href = "http://localhost:4444/y.html";
else
console.log("done");
});
win.location.href = "http://localhost:4444/x.html";
If you run your script only in Firefox, then you can use a simplified version and capture the document in a loading state, so for example a script on the loaded page cannot navigate away before you log the URI change:
var uuid = "win." + Math.random();
var timeOrigin = new Date();
var win = window.open("about:blank", uuid, "menubar=yes,location=yes,resizable=yes,scrollbars=yes,status=yes");
var callBacks = [];
win.addEventListener("unload", function unloadListener(){
setTimeout(function (){
callBacks.forEach(function (cb){
cb();
});
}, 0);
});
callBacks.push(function (){
console.log("cb", win.location.href, win.document.readyState);
// be aware that the page is in loading readyState,
// so if you rewrite the location here, the actual page will be never loaded, just the new one
if (win.location.href !== "http://localhost:4444/y.html")
win.location.href = "http://localhost:4444/y.html";
else
console.log("done");
});
win.location.href = "http://localhost:4444/x.html";
If we are talking about single page applications which change the hash part of the URI, or use the history API, then you can use the hashchange
and the popstate
events of the window respectively. Those can capture even if you move in history back and forward until you stay on the same page. The document does not changes by those and the page is not really reloaded.