The problem
In SvelteKit, I am trying to disable and enable scroll when my side menu is opened. To do that, I am trying to utilize the {open} variable that is bound to my menu icon with bind:open={open}.
I want to trigger the function enableScroll() when open is true, and trigger the function disableScroll() when open is false.
Both functions work fine. The {open} variable is true when I expect it to, and false when I expect it to when I use console.log().
The problem is that my if-block doesn't respond to {open} changing.
What I've tried
I have tried wrapping my if-block in another function and calling the function changeScroll() on:click.
I have tried
adapting the conditionals: if === true, true, open || null; similarly for the negation.
I have tried using a ternary operator inside of the binding like so: on:click={open ? disableScroll() : enableScroll() }
Currently, my code looks like this:
$: if (open === true) {
onMount(() => {
disableScroll()
})
} else if (open === false) {
onMount(() => {
enableScroll()
})
}
Perhaps I'm using onMount() wrongly? Or somehow I need to change my if statement to make it properly reactive / fix it some other way? I would gladly appreciate some help! Thank you.
onMount only queues a function to run once, when the component is mounted. So running onMount(() => { disableScroll() }) will not run disableScroll if the component has already been rendered -- any subsequent changes to open will not have any affect. This is why your code doesn't work.
However, you do need to do something to prevent your scroll code from running on the server, since window isn't available there. In SvelteKit, you can determine whether you're in the browser by using the browser import from $app/env. This will tell you if it's safe to access browser-only APIs on the document or window. So, you could do something like the following:
<script>
import { onMount } from 'svelte';
import { browser } from '$app/env';
let open;
let scrollTop = null;
let scrollLeft = null;
function disableScroll() {
if (browser) {
scrollTop =
window.pageYOffset || window.document.documentElement.scrollTop;
scrollLeft =
window.pageXOffset || window.document.documentElement.scrollLeft,
window.onscroll = function() {
window.scrollTo(scrollLeft, scrollTop);
}};
}
function enableScroll() {
if (browser) {
window.onscroll = function() {};
}
};
$: if (open) {
disableScroll();
} else {
enableScroll();
}
</script>
Related
I'm using React js. I need to detect page refresh. When user hits refresh icon or press F5, I need to find out the event.
I tried with stackoverflow post by using javascript functions
I used javascript function beforeunload still no luck.
onUnload(event) {
alert('page Refreshed')
}
componentDidMount() {
window.addEventListener("beforeunload", this.onUnload)
}
componentWillUnmount() {
window.removeEventListener("beforeunload", this.onUnload)
}
here I have full code on stackblitz
If you're using React Hook, UseEffect you can put the below changes in your component. It worked for me
useEffect(() => {
window.addEventListener("beforeunload", alertUser);
return () => {
window.removeEventListener("beforeunload", alertUser);
};
}, []);
const alertUser = (e) => {
e.preventDefault();
e.returnValue = "";
};
Place this in the constructor:
if (window.performance) {
if (performance.navigation.type == 1) {
alert( "This page is reloaded" );
} else {
alert( "This page is not reloaded");
}
}
It will work, please see this example on stackblitz.
It is actually quite straightforward, this will add the default alert whenever you reload your page.
In this answer you will find:
Default usage
Alert with validation
1. Default Usage
Functional Component
useEffect(() => {
window.onbeforeunload = function() {
return true;
};
return () => {
window.onbeforeunload = null;
};
}, []);
Class Component
componentDidMount(){
window.onbeforeunload = function() {
return true;
};
}
componentDidUnmount(){
window.onbeforeunload = null;
}
2. Alert with validation
You can put validation to only add alert whenever the condition is true.
Functional Component
useEffect(() => {
if (condition) {
window.onbeforeunload = function() {
return true;
};
}
return () => {
window.onbeforeunload = null;
};
}, [condition]);
Class Component
componentDidMount(){
if (condition) {
window.onbeforeunload = function() {
return true;
};
}
}
componentDidUnmount(){
window.onbeforeunload = null;
}
Your code seems to be working just fine, your alert won't work because you aren't stopping the refresh. If you console.log('hello') the output is shown.
UPDATE ---
This should stop the user refreshing but it depends on what you want to happen.
componentDidMount() {
window.onbeforeunload = function() {
this.onUnload();
return "";
}.bind(this);
}
Unfortunately currently accepted answer cannot be more considered as acceptable since performance.navigation.type is deprecated
The newest API for that is experimental ATM.
As a workaround I can only suggest to save some value in redux (or whatever you use) store to indicate state after reload and on first route change update it to indicate that route was changed not because of refresh.
If you are using either REDUX or CONTEXT API then its quite easy. You can check the REDUX or CONTEXT state variables. When the user refreshes the page it reset the CONTEXT or REDUX state and you have to set them manually again. So if they are not set or equal to the initial value which you have given then you can assume that the page is refreshed.
I have a problem that i never had before.
I wanna call a function when a mobile device change is orientation, so i'm using "onorientationchange" and to be sure it's triggered, i also use "onresize".
The problem is that the even don't work on the page for a mysterious reason :
if i do
document.body.addEventListener("resize",function(){console.log("here")};
it doesn't work, I so created a custom version of AddEventListener :
function addNewEvent(elementDOM, evenement, fonction){
var refEvent = null;
if(elementDOM)
{
elementDOM["on"+evenement] = fonction;
if (elementDOM.attachEvent)
{
refEvent =function() {
return fonction.call(elementDOM,window.event);
};
elementDOM.attachEvent ('on'+evenement,refEvent);
}
else if (elementDOM.addEventListener)
{
refEvent = fonction;
elementDOM.addEventListener (evenement,refEvent,false);
}
else
{
elementDOM["on"+evenement] = fonction;
}
}
return refEvent;
},
And even this one don't work...
BUT this works :
document.body.onresize = function(){console.log("here")};
it's a normal webpage, i don't get why it doesn't work.
Can you help? :x
resize events fire on the window object, not the body element.
You're listening for it in the wrong place.
window.addEventListener("resize",function(e){console.log("here", e.target)};
I've created a Backbone, Marionette and Require.js application and am now trying to add smooth transitioning between regions.
To do this easily* ive decided to extend the marionette code so it works across all my pages (theres a lot of pages so doing it manually would be too much)
Im extending the marionette.region open and close function. Problem is that it now doesnt call the onClose function inside each of my views.
If I add the code directly to the marionette file it works fine. So I'm probably merging the functions incorrectly, right?
Here is my code:
extendMarrionette: function () {
_.extend(Marionette.Region.prototype, {
open : function (view) {
var that = this;
// if this is the main content and should transition
if (this.$el.attr("id") === "wrapper" && document.wrapperIsHidden === true) {
this.$el.empty().append(view.el);
$(document).trigger("WrapperContentChanged")
} else if (this.$el.attr("id") === "wrapper" && document.wrapperIsHidden === false) {
$(document).on("WrapperIsHidden:open", function () {
//swap content
that.$el.empty().append(view.el);
//tell router to transition in
$(document).trigger("WrapperContentChanged");
//remove this event listener
$(document).off("WrapperIsHidden:open", that);
});
} else {
this.$el.empty().append(view.el);
}
},
//A new function Ive added - was originally inside the close function below. Now the close function calls this function.
kill : function (that) {
var view = this.currentView;
$(document).off("WrapperIsHidden:close", that)
if (!view || view.isClosed) {
return;
}
// call 'close' or 'remove', depending on which is found
if (view.close) {
view.close();
}
else if (view.remove) {
view.remove();
}
Marionette.triggerMethod.call(that, "close", view);
delete this.currentView;
},
// Close the current view, if there is one. If there is no
// current view, it does nothing and returns immediately.
close : function () {
var view = this.currentView;
var that = this;
if (!view || view.isClosed) {
return;
}
if (this.$el.attr("id") === "wrapper" && document.wrapperIsHidden === true) {
this.kill(this);
} else if (this.$el.attr("id") === "wrapper" && document.wrapperIsHidden === false) {
//Browser bug fix - needs set time out
setTimeout(function () {
$(document).on("WrapperIsHidden:close", that.kill(that));
}, 10)
} else {
this.kill(this);
}
}
});
}
Why don't you extend the Marionette.Region? That way you can choose between using your custom Region class, or the original one if you don't need the smooth transition in all cases. (And you can always extend it again if you need some specific behavior for some specific case).
https://github.com/marionettejs/backbone.marionette/blob/master/docs/marionette.region.md#region-class
var MyRegion = Marionette.Region.extend({
open: function() {
//Your open function
}
kill: function() {
//Your kill function
}
close: function() {
//Your close function
}
});
App.addRegions({
navigationRegion: MyRegion
});
Perhaps your issue is that you are not passing a function to your event listener, but instead calling the code directly in the code below.
setTimeout(function(){
$(document).on("WrapperIsHidden:close", that.kill(that));
}, 10)
It is likely that you want something like this:
setTimeout(function(){
$(document).on("WrapperIsHidden:close", function (){ that.kill(that); });
}, 10)
Another possible problem is that you are mixing up your references to this/that in your kill function. It seems like you probably want var view to either be assigned to that.view or to use this rather than that throughout the method.
Answer to your additional problems:
You should try passing the view variable from the close function directly into your kill function because the reference to currentView is already changed to the new view object when you actually want to old view object. The reason this is happening is that you are setting a timeout before executing the kill function. You can see this if you look at the show source code. It expects close, open and then currentView assignment to happen synchronously in order.
main question
Is there a javascript way to identify if we are accessing a page for the first time or it is a cause of a back?
My problem
I'm implementing html5 navigation in my ajax driven webpage.
On the main script, I initialize a variable with some values.
<script>
var awnsers=[];
process(awnsers);
<script>
Process(awnsers) will update the view according to the given awnsers, using ajax.
In the funciton that calls ajax, and replaces the view, I store the history
history.pushState(state, "", "");
I defined the popstate also, where I restore the view according to the back. Moreover, I modify the global variable awnsers for the old value.
function popState(event) {
if (event.state) {
state = event.state;
awnsers=state.awnsers;
updateView(state.view);
}
}
Navigation (back and forth) goes corectly except when I go to an external page, and press back (arrving to my page again).
As we are accessing the page, first, the main script is called,the valiable awnsers is updated, and the ajax starts. Meanwile, the pop state event is called, and updates the view. After that the main ajax ends, and updates the view according to empty values.
So I need the code:
<script>
var awnsers=[];
process(awnsers);
<script>
only be called when the user enters the page but NOT when it is a back. Any way to do this?
THanks!
Possible solution
After the first awnser I have thought of a possible solution. Tested and works, whoever, I don't know if there is any cleaner solution. I add the changes that I've done.
First I add:
$(function() {
justLoaded=true;
});
then I modify the popState function, so that is in charge to initialize the variables
function popState(event) {
if (event.state) {
state = event.state;
awnsers=state.awnsers;
updateView(state.view);
} else if(justLoaded){
awnsers=[];
process(awnsers);
}
justLoaded=false;
}
Thats all.
what about using a global variable?
var hasLoaded = false;
// this function can be called by dom ready or window load
function onPageLoad() {
hasLoaded = true;
}
// this function is called when you user presses browser back button and they are still on your page
function onBack() {
if (hasLoaded) {
// came by back button and page was loaded
}
else {
// page wasn't loaded. this is first visit of the page
}
}
Use cookie to store the current state.
yeah! This is what I have:
var popped = (($.browser.msie && parseInt($.browser.version, 10) < 9) ? 'state' in window.history : window.history.hasOwnProperty('state')), initialURL = location.href;
$(window).on('popstate', function (event) {
var initialPop = !popped && location.href === initialURL, state;
popped = true;
if (initialPop) { return; }
state = event.originalEvent.state;
if (state && state.reset) {
if (history.state === state) {
$.ajax({url: state.loc,
success: function (response) {
$(".fragment").fadeOut(100, function () {
$(".fragment").html($(".fragment", response).html()).fadeIn(100);
);
document.title = response.match(/<title>(.*)<\/title>/)[1];
}
});
} else { history.go(0); }
else {window.location = window.location.href; }
});
And:
$.ajax({url:link,
success: function (response) {
var replace = args.replace.split(",");
$.each(replace, function (i) {
replace[i] += ($(replace[i]).find("#video-content").length > 0) ? " #video-content" : "";
var selector = ".fragment "+replace[i];
$(selector).fadeOut(100, function () {
$(selector).html($(selector,response).html()).fadeIn(100, function () {
if (base.children("span[data-video]")[0]) {
if ($.browser.msie && parseInt($.browser.version, 10) === 7) {
$("#theVideo").html("");
_.videoPlayer();
} else {
_.player.cueVideoById(base.children("span[data-video]").attr("data-video"));
}
}
});
});
});
document.title = response.match(/<title>(.*)<\/title>/)[1];
window.history.ready = true;
if (history && history.pushState) { history.pushState({reset:true, loc:link}, null, link); }
}
});
What's the correct way of detecting when an iframe gets or loses focus (i.e. will or will not receive keyboard events)? The following is not working in Fx4:
var iframe = /* my iframe */;
iframe.addEventListener("focus", function() { /* never gets called */ }, false);
You can poll "document.activeElement" to determine if it matches the iframe. Polling isn't ideal, but it works:
function checkFocus() {
if(document.activeElement == document.getElementsByTagName("iframe")[0]) {
console.log('iframe has focus');
} else {
console.log('iframe not focused');
}
}
window.setInterval(checkFocus, 1000);
i know it's old, but i also had the same problem.
i ended up using this little pice of code:
$(document).on('focusout', function(){
setTimeout(function(){
// using the 'setTimout' to let the event pass the run loop
if (document.activeElement instanceof HTMLIFrameElement) {
// Do your logic here..
}
},0);
});
Turns out it's not really possible. I had to change the logic of my page to avoid the need of tracking if the iframe has focus.
How to check when an iframe has been clicked in or out of as well as hover-state.
Note: I would highly recommend you don't choose a polling method and go with an event driven method such as this.
Disclaimer
It is not possible to use the focus or blur events directly on an iframe but you can use them on the window to provide an event driven method of checking the document.activeElement. Thus you can accomplish what you're after.
Although we're now in 2018, my code is being implemented in GTM and tries to be cross browser compatible back to IE 11. This means there's more efficient code if you're utilizing newer ES/ECMAScript features.
Setup
I'm going to take this a few steps further to show that we can also get the iframe's src attribute as well as determine if it's being hovered.
Code
You would ideally need to put this in a document ready event, or at least encapsulate it so that the variables aren't global [maybe use an IIFE]. I did not wrap it in a document ready because it's handled by GTM. It may also depend where you place this or how you're loading it such as in the footer.
https://jsfiddle.net/9285tbsm/9/
I have noticed in the JSFiddle preview that it's already an iframe, sometimes you have to focus it first before events start to capture. Other issues can be that your browser window isn't yet focused either.
// Helpers
var iframeClickedLast;
function eventFromIframe(event) {
var el = event.target;
return el && el.tagName && el.tagName.toLowerCase() == 'iframe';
}
function getIframeSrc(event) {
var el = event.target;
return eventFromIframe(event) ? el.getAttribute('src') : '';
}
// Events
function windowBlurred(e) {
var el = document.activeElement;
if (el.tagName.toLowerCase() == 'iframe') {
console.log('Blurred: iframe CLICKED ON', 'SRC:', el.getAttribute('src'), e);
iframeClickedLast = true;
}
else {
console.log('Blurred', e);
}
}
function windowFocussed(e) {
if (iframeClickedLast) {
var el = document.activeElement;
iframeClickedLast = false;
console.log('Focussed: iframe CLICKED OFF', 'SRC:', el.getAttribute('src'), e);
}
else {
console.log('Focussed', e);
}
}
function iframeMouseOver(e) {
console.log('Mouse Over', 'SRC:', getIframeSrc(e), e);
}
function iframeMouseOut(e) {
console.log('Mouse Out', 'SRC:', getIframeSrc(e), e);
}
// Attach Events
window.addEventListener('focus', windowFocussed, true);
window.addEventListener('blur', windowBlurred, true);
var iframes = document.getElementsByTagName("iframe");
for (var i = 0; i < iframes.length; i++) {
iframes[i].addEventListener('mouseover', iframeMouseOver, true);
iframes[i].addEventListener('mouseout', iframeMouseOut, true);
}
I have solved this by using contentWindow instead of contentDocument.
The good thing about contentWindow is
it works also in case user clicks another window (another application) or another browser tab. If using activeElement, if user clicks away from the entire window to go to another application, then that logic still think the iframe is in focus, while it is not
and we don't need to poll and do a setInterval at all. This uses the normal addEventListener
let iframe = document.getElementsByTagName("iframe")[0];
// or whatever way you do to grab that iFrame, say you have an `id`, then it's even more precise
if(iframe){
iframeWindow = iframe.contentWindow;
iframeWindow.addEventListener('focus', handleIframeFocused);
iframeWindow.addEventListener('blur', handleIframeBlurred);
}
function handleIframeFocused(){
console.log('iframe focused');
// Additional logic that you need to implement here when focused
}
function handleIframeBlurred(){
console.log('iframe blurred');
// Additional logic that you need to implement here when blurred
}
This solution is working for me on both mobile and desktop:
;(function pollForIframe() {
var myIframe = document.querySelector('#my_iframe');
if (!myIframe) return setTimeout(pollForIframe, 50);
window.addEventListener('blur', function () {
if (document.activeElement == myIframe) {
console.log('myIframe clicked!');
}
});
})();
The solution is to inject a javascript event on the parent page like this :
var script = document.createElement('script');
script.type = 'text/javascript';
script.innerHTML =
"document.addEventListener('click', function()" +
"{ if(document.getElementById('iframe')) {" +
// What you want
"}});";
head.appendChild(script);
Here is the code to Detecting when an iframe gets or loses focus
// This code can be used to verify Iframe gets focus/loses.
function CheckFocus(){
if (document.activeElement.id == $(':focus').context.activeElement.id) {
// here do something
}
else{
//do something
}
}
A compact function that accepts callbacks you want to run when iframe gets or loses focus.
/* eslint-disable no-unused-vars */
export default function watchIframeFocus(onFocus, onBlur) {
let iframeClickedLast;
function windowBlurred(e) {
const el = document.activeElement;
if (el.tagName.toLowerCase() == 'iframe') {
iframeClickedLast = true;
onFocus();
}
}
function windowFocussed(e) {
if (iframeClickedLast) {
iframeClickedLast = false;
onBlur();
}
}
window.addEventListener('focus', windowFocussed, true);
window.addEventListener('blur', windowBlurred, true);
}
This might work
document.addEventListener('click', function(event) {
var frame= document.getElementById("yourFrameID");
var isClickInsideFrame = frame.contains(event.target);
if (!isClickInsideFrame ) {
//exec code
}
});