How can I check if a URL has changed in JavaScript? For example, websites like GitHub, which use AJAX, will append page information after a # symbol to create a unique URL without reloading the page. What is the best way to detect if this URL changes?
Is the onload event called again?
Is there an event handler for the URL?
Or must the URL be checked every second to detect a change?
I wanted to be able to add locationchange event listeners. After the modification below, we'll be able to do it, like this
window.addEventListener('locationchange', function () {
console.log('location changed!');
});
In contrast, window.addEventListener('hashchange',() => {}) would only fire if the part after a hashtag in a url changes, and window.addEventListener('popstate',() => {}) doesn't always work.
This modification, similar to Christian's answer, modifies the history object to add some functionality.
By default, before these modifications, there's a popstate event, but there are no events for pushstate, and replacestate.
This modifies these three functions so that all fire a custom locationchange event for you to use, and also pushstate and replacestate events if you want to use those.
These are the modifications:
(() => {
let oldPushState = history.pushState;
history.pushState = function pushState() {
let ret = oldPushState.apply(this, arguments);
window.dispatchEvent(new Event('pushstate'));
window.dispatchEvent(new Event('locationchange'));
return ret;
};
let oldReplaceState = history.replaceState;
history.replaceState = function replaceState() {
let ret = oldReplaceState.apply(this, arguments);
window.dispatchEvent(new Event('replacestate'));
window.dispatchEvent(new Event('locationchange'));
return ret;
};
window.addEventListener('popstate', () => {
window.dispatchEvent(new Event('locationchange'));
});
})();
Note, we're creating a closure, to save the old function as part of the new one, so that it gets called whenever the new one is called.
In modern browsers (IE8+, FF3.6+, Chrome), you can just listen to the hashchange event on window.
In some old browsers, you need a timer that continually checks location.hash. If you're using jQuery, there is a plugin that does exactly that.
Example
Below I undo any URL change, to keep just the scrolling:
<script type="text/javascript">
if (window.history) {
var myOldUrl = window.location.href;
window.addEventListener('hashchange', function(){
window.history.pushState({}, null, myOldUrl);
});
}
</script>
Note that above used history-API is available in Chrome, Safari, Firefox 4+, and Internet Explorer 10pp4+
window.onhashchange = function() {
//code
}
window.onpopstate = function() {
//code
}
or
window.addEventListener('hashchange', function() {
//code
});
window.addEventListener('popstate', function() {
//code
});
with jQuery
$(window).bind('hashchange', function() {
//code
});
$(window).bind('popstate', function() {
//code
});
EDIT after a bit of researching:
It somehow seems that I have been fooled by the documentation present on Mozilla docs. The popstate event (and its callback function onpopstate) are not triggered whenever the pushState() or replaceState() are called in code. Therefore the original answer does not apply in all cases.
However there is a way to circumvent this by monkey-patching the functions according to #alpha123:
var pushState = history.pushState;
history.pushState = function () {
pushState.apply(history, arguments);
fireEvents('pushState', arguments); // Some event-handling function
};
Original answer
Given that the title of this question is "How to detect URL change" the answer, when you want to know when the full path changes (and not just the hash anchor), is that you can listen for the popstate event:
window.onpopstate = function(event) {
console.log("location: " + document.location + ", state: " + JSON.stringify(event.state));
};
Reference for popstate in Mozilla Docs
Currently (Jan 2017) there is support for popstate from 92% of browsers worldwide.
With jquery (and a plug-in) you can do
$(window).bind('hashchange', function() {
/* things */
});
http://benalman.com/projects/jquery-hashchange-plugin/
Otherwise yes, you would have to use setInterval and check for a change in the hash event (window.location.hash)
Update! A simple draft
function hashHandler(){
this.oldHash = window.location.hash;
this.Check;
var that = this;
var detect = function(){
if(that.oldHash!=window.location.hash){
alert("HASH CHANGED - new has" + window.location.hash);
that.oldHash = window.location.hash;
}
};
this.Check = setInterval(function(){ detect() }, 100);
}
var hashDetection = new hashHandler();
Add a hash change event listener!
window.addEventListener('hashchange', function(e){console.log('hash changed')});
Or, to listen to all URL changes:
window.addEventListener('popstate', function(e){console.log('url changed')});
This is better than something like the code below because only one thing can exist in window.onhashchange and you'll possibly be overwriting someone else's code.
// Bad code example
window.onhashchange = function() {
// Code that overwrites whatever was previously in window.onhashchange
}
this solution worked for me:
function checkURLchange(){
if(window.location.href != oldURL){
alert("url changed!");
oldURL = window.location.href;
}
}
var oldURL = window.location.href;
setInterval(checkURLchange, 1000);
None of these seem to work when a link is clicked that which redirects you to a different page on the same domain. Hence, I made my own solution:
let pathname = location.pathname;
window.addEventListener("click", function() {
if (location.pathname != pathname) {
pathname = location.pathname;
// code
}
});
Edit: You can also check for the popstate event (if a user goes back a page)
window.addEventListener("popstate", function() {
// code
});
Best wishes,
Calculus
If none of the window events are working for you (as they aren't in my case), you can also use a MutationObserver that looks at the root element (non-recursively).
// capture the location at page load
let currentLocation = document.location.href;
const observer = new MutationObserver((mutationList) => {
if (currentLocation !== document.location.href) {
// location changed!
currentLocation = document.location.href;
// (do your event logic here)
}
});
observer.observe(
document.getElementById('root'),
{
childList: true,
// important for performance
subtree: false
});
This may not always be feasible, but typically, if the URL changes, the root element's contents change as well.
I have not profiled, but theoretically this has less overhead than a timer because the Observer pattern is typically implemented so that it just loops through the subscriptions when a change occurs. We only added one subscription here. The timer on the other hand would have to check very frequently in order to ensure that the event was triggered immediately after URL change.
Also, this has a good chance of being more reliable than a timer since it eliminates timing issues.
Although an old question, the Location-bar project is very useful.
var LocationBar = require("location-bar");
var locationBar = new LocationBar();
// listen to all changes to the location bar
locationBar.onChange(function (path) {
console.log("the current url is", path);
});
// listen to a specific change to location bar
// e.g. Backbone builds on top of this method to implement
// it's simple parametrized Backbone.Router
locationBar.route(/some\-regex/, function () {
// only called when the current url matches the regex
});
locationBar.start({
pushState: true
});
// update the address bar and add a new entry in browsers history
locationBar.update("/some/url?param=123");
// update the address bar but don't add the entry in history
locationBar.update("/some/url", {replace: true});
// update the address bar and call the `change` callback
locationBar.update("/some/url", {trigger: true});
To listen to url changes, see below:
window.onpopstate = function(event) {
console.log("location: " + document.location + ", state: " + JSON.stringify(event.state));
};
Use this style if you intend to stop/remove listener after some certain condition.
window.addEventListener('popstate', function(e) {
console.log('url changed')
});
The answer below comes from here(with old javascript syntax(no arrow function, support IE 10+)):
https://stackoverflow.com/a/52809105/9168962
(function() {
if (typeof window.CustomEvent === "function") return false; // If not IE
function CustomEvent(event, params) {
params = params || {bubbles: false, cancelable: false, detail: null};
var evt = document.createEvent("CustomEvent");
evt.initCustomEvent(event, params.bubbles, params.cancelable, params.detail);
return evt;
}
window.CustomEvent = CustomEvent;
})();
(function() {
history.pushState = function (f) {
return function pushState() {
var ret = f.apply(this, arguments);
window.dispatchEvent(new CustomEvent("pushState"));
window.dispatchEvent(new CustomEvent("locationchange"));
return ret;
};
}(history.pushState);
history.replaceState = function (f) {
return function replaceState() {
var ret = f.apply(this, arguments);
window.dispatchEvent(new CustomEvent("replaceState"));
window.dispatchEvent(new CustomEvent("locationchange"));
return ret;
};
}(history.replaceState);
window.addEventListener("popstate", function() {
window.dispatchEvent(new CustomEvent("locationchange"));
});
})();
While doing a little chrome extension, I faced the same problem with an additionnal problem : Sometimes, the page change but not the URL.
For instance, just go to the Facebook Homepage, and click on the 'Home' button. You will reload the page but the URL won't change (one-page app style).
99% of the time, we are developping websites so we can get those events from Frameworks like Angular, React, Vue etc..
BUT, in my case of a Chrome extension (in Vanilla JS), I had to listen to an event that will trigger for each "page change", which can generally be caught by URL changed, but sometimes it doesn't.
My homemade solution was the following :
listen(window.history.length);
var oldLength = -1;
function listen(currentLength) {
if (currentLength != oldLength) {
// Do your stuff here
}
oldLength = window.history.length;
setTimeout(function () {
listen(window.history.length);
}, 1000);
}
So basically the leoneckert solution, applied to window history, which will change when a page changes in a single page app.
Not rocket science, but cleanest solution I found, considering we are only checking an integer equality here, and not bigger objects or the whole DOM.
Found a working answer in a separate thread:
There's no one event that will always work, and monkey patching the pushState event is pretty hit or miss for most major SPAs.
So smart polling is what's worked best for me. You can add as many event types as you like, but these seem to be doing a really good job for me.
Written for TS, but easily modifiable:
const locationChangeEventType = "MY_APP-location-change";
// called on creation and every url change
export function observeUrlChanges(cb: (loc: Location) => any) {
assertLocationChangeObserver();
window.addEventListener(locationChangeEventType, () => cb(window.location));
cb(window.location);
}
function assertLocationChangeObserver() {
const state = window as any as { MY_APP_locationWatchSetup: any };
if (state.MY_APP_locationWatchSetup) { return; }
state.MY_APP_locationWatchSetup = true;
let lastHref = location.href;
["popstate", "click", "keydown", "keyup", "touchstart", "touchend"].forEach((eventType) => {
window.addEventListener(eventType, () => {
requestAnimationFrame(() => {
const currentHref = location.href;
if (currentHref !== lastHref) {
lastHref = currentHref;
window.dispatchEvent(new Event(locationChangeEventType));
}
})
})
});
}
Usage
observeUrlChanges((loc) => {
console.log(loc.href)
})
I created this event that is very similar to the hashchange event
// onurlchange-event.js v1.0.1
(() => {
const hasNativeEvent = Object.keys(window).includes('onurlchange')
if (!hasNativeEvent) {
let oldURL = location.href
setInterval(() => {
const newURL = location.href
if (oldURL === newURL) {
return
}
const urlChangeEvent = new CustomEvent('urlchange', {
detail: {
oldURL,
newURL
}
})
oldURL = newURL
dispatchEvent(urlChangeEvent)
}, 25)
addEventListener('urlchange', event => {
if (typeof(onurlchange) === 'function') {
onurlchange(event)
}
})
}
})()
Example of use:
window.onurlchange = event => {
console.log(event)
console.log(event.detail.oldURL)
console.log(event.detail.newURL)
}
addEventListener('urlchange', event => {
console.log(event)
console.log(event.detail.oldURL)
console.log(event.detail.newURL)
})
for Chrome 102+ (2022-05-24)
navigation.addEventListener("navigate", e => {
console.log(`navigate ->`,e.destination.url)
});
API references WICG/navigation-api
Look at the jQuery unload function. It handles all the things.
https://api.jquery.com/unload/
The unload event is sent to the window element when the user navigates away from the page. This could mean one of many things. The user could have clicked on a link to leave the page, or typed in a new URL in the address bar. The forward and back buttons will trigger the event. Closing the browser window will cause the event to be triggered. Even a page reload will first create an unload event.
$(window).unload(
function(event) {
alert("navigating");
}
);
window.addEventListener("beforeunload", function (e) {
// do something
}, false);
You are starting a new setInterval at each call, without cancelling the previous one - probably you only meant to have a setTimeout
Enjoy!
var previousUrl = '';
var observer = new MutationObserver(function(mutations) {
if (location.href !== previousUrl) {
previousUrl = location.href;
console.log(`URL changed to ${location.href}`);
}
});
Another simple way you can do this is by adding a click event, through a class name to the anchor tags on the page to detect when it has been clicked, then you can now use the window.location.href to get the url data which you can use to run your ajax request to the server. Simple and Easy.
I’m working on an eshop where items are opened on top of a page in iframes. I’m using
history.pushState(stateObj, "page 2", http://localhost:8888/product-category/tyger/vara-tyger/?view=product&item=test-4);
in order to let customers copy the current url and use it to go to the current page with the item opened in an iframe. In addition, I’m using
window.addEventListener('popstate', manageHistory);
function manageHistory(event) {
if (!has_gone_back) {
var iframeOpen = false;
has_gone_back = true;
}
else {
var iframeOpen = true;
has_gone_back = false;
}
}
in order to let customers use their browser’s back and forward buttons for navigation (closing and opening the iframe).
However, when opening one product (calling history.pushState once), using the browser’s back button, and opening another product (calling history.pushState again), and going back again, manageHistory() is not called. The customer is taken to the first opened product but if pressing back again, manageHistory() is called.
I want manageHistory() to be called when pressing back on the product page opened second in order to add code to redirect customers to the category's start page when pressing back.
I’ve tried both adding Event Listeners for both opened products and also for only the first one. Any ideas what the problem may be?
From https://developer.mozilla.org/en-US/docs/Web/Events/popstate
Note that just calling history.pushState() or history.replaceState() won't trigger a popstate event. The popstate event is only triggered by doing a browser action such as a click on the back button (or calling history.back() in JavaScript).
You can overwrite popState and replaceState, but what is generally a better idea is to create a wrapper which sets the url and then triggers your handler function.
Something like this...
function urlChangeHandler() {
var url = window.location.href;
// Whatever you want to do...
}
// Handle initial url:
urlChangeHandler();
window.addEventListener('popstate', urlChangeHandler);
var urlState = {
push: function(url) {
window.history.pushState(null, null, url);
urlChangeHandler();
},
replace: function(url) {
window.history.replaceState(null, null, url);
urlChangeHandler();
}
}
I have a similar file in one of my projects which updates the datastore based on the #hash...
import tree from './state'
// No need for react-router for such a simple application.
function hashChangeHandler(commit) {
return () => {
const hash = window.location.hash.substr(1);
const cursor = tree.select('activeContactIndex');
const createCursor = tree.select('createNewContact');
cursor.set(null);
createCursor.set(false);
(() => {
if(!hash.length) {
// Clean up the url (remove the hash if there is nothing after it):
window.history.replaceState(null, null, window.location.pathname);
return;
}
if(hash === 'new') {
createCursor.set(true);
return;
}
const index = parseInt(hash, 10);
if(!isNaN(index)) {
cursor.set(index);
}
})();
commit && tree.commit();
}
}
// Handle initial url:
hashChangeHandler(true)();
// Handle manual changes of the hash in the url:
window.addEventListener('hashchange', hashChangeHandler(true));
function createHash(location) {
return (location !== null) ? `#${location}` : window.location.pathname;
}
module.exports = {
push: (location, commit=true) => {
window.history.pushState(null, null, createHash(location));
hashChangeHandler(commit)();
},
replace: (location, commit=true) => {
window.history.replaceState(null, null, createHash(location));
hashChangeHandler(commit)();
}
}
I'm new to backboneJs.
Currently when i do browser refresh, it takes back me to login page.
var AppRouter = Backbone.Router.extend({
routes : {
// Pages
'startup' : 'LoginScreen',
'Home' : 'HomeScreen',
'AssetDetail':'AssetScreen',
'*actions' : 'LoginScreen'
},
...
});
var initialize = function(options) {
var appView = options.appView;
var router = new AppRouter(options);
router.on('route:LoginScreen', function(actions) {
require([ 'login/LoginView' ], function(StartView) {
console.log(" --route login");
var startView = new StartView();
});
});
router.on('route:HomeScreen', function(actions) {
require([ 'home/HomeView' ], function(HomeScreenView) {
console.log(" --route home");
var homeScreenView = new HomeScreenView();
});
});
router.on('route:AssetDetailScreen', function(actions) {
require([ 'views/AssetDetailView' ], function(AssetDetailScreenView) {
var assetdetailScreenView = new AssetDetailScreenView();
});
});
Backbone.history.start({pushState: true});
};
So lets say my current url is http://localhost:8080/myapp/# , and when i do browser refresh (F5 may be) , I want to load the same page.
How do I do it ?, Help me!
Not me who originally wrote this answer but I think it's the best solution.
*"You can call Backbone.history.loadUrl.
To refresh the current page:
*`Backbone.history.loadUrl(Backbone.history.fragment);`*
Or as a link handler:
// Backbone.history.navigate is sufficient for all Routers and will trigger the
// correct events. The Router's internal navigate method calls this anyways.
var ret = Backbone.history.navigate(href, true);
// Typically Backbone's history/router will do nothing when trying to load the same URL.
// But since we want it to re-fire the same route, we can detect
// when Backbone.history.navigate did nothing, and force the route.
if (ret === undefined) {
Backbone.history.loadUrl(href);
}"*
Backbone: Refresh the same route path for twice
I am using sammy.js for single page application in asp.net mvc. Everything is fine, but I am facing one problem which is that I can not reload the page. For example When I am in the dashboard my URL is
http://localhost:1834/#/Home/Index?lblbreadcum=Dashboard
layout.cshtml
<script>
$(function () {
var routing = new Routing('#Url.Content("~/")', '#page', 'welcome');
routing.init();
});
</script>
routing.js
var Routing = function (appRoot, contentSelector, defaultRoute) {
function getUrlFromHash(hash) {
var url = hash.replace('#/', '');
if (url === appRoot)
url = defaultRoute;
return url;
}
return {
init: function () {
Sammy(contentSelector, function () {
this.get(/\#\/(.*)/, function (context) {
var url = getUrlFromHash(context.path);
context.load(url).swap();
});
}).run('#/');
}
};
}
I want to reload the page by clicking the dashboard menu/link. But click event not firing because link is not changing. But if I want to go another page then it is fine. Please help me out. Thanks.
I think you have to append the same partial again. You can't "update" the partial in that meaning.
As you say in your post, when you click another link and then back again it works.
That's what you'll have to do. Append the same page/partial again, by doing that you clear all variables and recreate them, by that simulating a refresh.
EDIT: Added example
Observe that I didn't copy your code straight off but I think you'll understand :)
And I don't use hash (#) in my example.
var app = Sammy(function () {
this.get('/', function (context) {
// context is equalient to data.app in the custom bind example
// currentComponent('home'); I use components in my code but you should be able to swith to your implementation
var url = getUrlFromHash(context.path);
context.load(url).swap();
});
this.bind('mycustom-trigger', function (e, data) {
this.redirect('/'); // force redirect
});
this.get('/about', function (evt) {
// currentComponent('about'); I use components in my code but you should be able to swith to your implementation
var url = getUrlFromHash(context.path);
context.load(url).swap();
});
}).run();
// I did an easy example trigger here but I think you will need a trigger on your link-element. Mayby with a conditional check wheter or not to trigger the manually binding or not
$('.navbar-collapse').click(function () {
app.trigger('mycustom-trigger', app);
});
Please read more about events and routing in sammy.js
Good luck :)
An easier and cleaner way to force the route to reload is to call the Sammy.Application refresh() method:
import { sammyApp } from '../mySammyApp';
const url = `${mySearchRoute}/${encodeURIComponent(this.state.searchText)}`;
if (window.location.hash === url) {
sammyApp.refresh();
else {
window.location.hash = url;
}
I have some functionality that i need to change whenever the path changes. Often you would solve that problem with the following.
myProp: ( ->
# .. Do something here
).property('currentPath')
The problem with currentPath, is that it only detect route changes, so the following transition is not detected.
/blog/my-awesome-blog-post -> /blog/new-awesome-post
Because they are working on the same route, but i need to detect when a transition like that happens, as i need to update my social media sharing links.
I have tried something like the following with no luck.
App = Ember.Application.create({
conf: config,
currentPathName: '',
});
App.initializer({
name: 'Path name observer',
initialize: function(container, application) {
var router = container.lookup('router:main');
router.addObserver('url', function() {
var lastUrl = undefined;
return function() {
Ember.run.next(function() {
var url = router.get('url');
if (url !== lastUrl) {
App.set('currentPathName', url);
lastUrl = url;
}
});
};
}());
}
});
And then observe 'App.currentPathName', but this somehow messes the router up, as the url's suddenly doesn't change on click.
Any suggestions?
This is the solution i got from a friendly soul # github. This is not currently documented, but works quiet nicely.
Ember.Router.reopen({
doSomethingOnUrlChange: function() {
console.log(this.get('url'));
}.on('didTransition')
});