Develop Reference

Detect URL if it is already opened and throw pop-up : HTML+JS [duplicate]

I want to check with JavaScript if the user has already opened my website in another tab in their browser.
It seems I cannot do that with pagevisibility...
The only way I see is to use WebSocket based on a session cookie, and check if the client has more than one socket. But by this way, from current tab, I have to ask my server if this user has a tab opened right next to their current browser tab. It is a little far-fetched!
Maybe with localstorage?

The shorter version with localStorage and Storage listener
<script type="text/javascript">
// Broadcast that you're opening a page.
localStorage.openpages = Date.now();
var onLocalStorageEvent = function(e){
if(e.key == "openpages"){
// Listen if anybody else is opening the same page!
localStorage.page_available = Date.now();
}
if(e.key == "page_available"){
alert("One more page already open");
}
};
window.addEventListener('storage', onLocalStorageEvent, false);
</script>
Update:
Works on page crash as well.
Stimulate page crash in chrome: chrome://inducebrowsercrashforrealz
Live demo

Using local storage I created a simple demo that should accomplish what your looking to do. Basically, it simply maintains a count of currently opened windows. When the window is closed the unload events fire and remove it from the total window count.
When you first look at it, you may think there's more going on than there really is. Most of it was a shotty attempt to add logic into who was the "main" window, and who should take over as the "main" window as you closed children. (Hence the setTimeout calls to recheck if it should be promoted to a main window) After some head scratching, I decided it would take too much time to implement and was outside the scope of this question. However, if you have two windows open (Main, and Child) and you close the Main, the child will be promoted to a main.
For the most part you should be able to get the general idea of whats going on and use it for your own implementation.
See it all in action here:
http://jsbin.com/mipanuro/1/edit
Oh yeah, to actually see it in action... Open the link in multiple windows. :)
Update:
I've made the necessary changes to have the the local storage maintain the "main" window. As you close tabs child windows can then become promoted to a main window. There are two ways to control the "main" window state through a parameter passed to the constructor of WindowStateManager. This implementation is much nicer than my previous attempt.
JavaScript:
// noprotect
var statusWindow = document.getElementById('status');
(function (win)
{
//Private variables
var _LOCALSTORAGE_KEY = 'WINDOW_VALIDATION';
var RECHECK_WINDOW_DELAY_MS = 100;
var _initialized = false;
var _isMainWindow = false;
var _unloaded = false;
var _windowArray;
var _windowId;
var _isNewWindowPromotedToMain = false;
var _onWindowUpdated;
function WindowStateManager(isNewWindowPromotedToMain, onWindowUpdated)
{
//this.resetWindows();
_onWindowUpdated = onWindowUpdated;
_isNewWindowPromotedToMain = isNewWindowPromotedToMain;
_windowId = Date.now().toString();
bindUnload();
determineWindowState.call(this);
_initialized = true;
_onWindowUpdated.call(this);
}
//Determine the state of the window
//If its a main or child window
function determineWindowState()
{
var self = this;
var _previousState = _isMainWindow;
_windowArray = localStorage.getItem(_LOCALSTORAGE_KEY);
if (_windowArray === null || _windowArray === "NaN")
{
_windowArray = [];
}
else
{
_windowArray = JSON.parse(_windowArray);
}
if (_initialized)
{
//Determine if this window should be promoted
if (_windowArray.length <= 1 ||
(_isNewWindowPromotedToMain ? _windowArray[_windowArray.length - 1] : _windowArray[0]) === _windowId)
{
_isMainWindow = true;
}
else
{
_isMainWindow = false;
}
}
else
{
if (_windowArray.length === 0)
{
_isMainWindow = true;
_windowArray[0] = _windowId;
localStorage.setItem(_LOCALSTORAGE_KEY, JSON.stringify(_windowArray));
}
else
{
_isMainWindow = false;
_windowArray.push(_windowId);
localStorage.setItem(_LOCALSTORAGE_KEY, JSON.stringify(_windowArray));
}
}
//If the window state has been updated invoke callback
if (_previousState !== _isMainWindow)
{
_onWindowUpdated.call(this);
}
//Perform a recheck of the window on a delay
setTimeout(function()
{
determineWindowState.call(self);
}, RECHECK_WINDOW_DELAY_MS);
}
//Remove the window from the global count
function removeWindow()
{
var __windowArray = JSON.parse(localStorage.getItem(_LOCALSTORAGE_KEY));
for (var i = 0, length = __windowArray.length; i < length; i++)
{
if (__windowArray[i] === _windowId)
{
__windowArray.splice(i, 1);
break;
}
}
//Update the local storage with the new array
localStorage.setItem(_LOCALSTORAGE_KEY, JSON.stringify(__windowArray));
}
//Bind unloading events
function bindUnload()
{
win.addEventListener('beforeunload', function ()
{
if (!_unloaded)
{
removeWindow();
}
});
win.addEventListener('unload', function ()
{
if (!_unloaded)
{
removeWindow();
}
});
}
WindowStateManager.prototype.isMainWindow = function ()
{
return _isMainWindow;
};
WindowStateManager.prototype.resetWindows = function ()
{
localStorage.removeItem(_LOCALSTORAGE_KEY);
};
win.WindowStateManager = WindowStateManager;
})(window);
var WindowStateManager = new WindowStateManager(false, windowUpdated);
function windowUpdated()
{
//"this" is a reference to the WindowStateManager
statusWindow.className = (this.isMainWindow() ? 'main' : 'child');
}
//Resets the count in case something goes wrong in code
//WindowStateManager.resetWindows()
HTML:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JS Bin</title>
</head>
<body>
<div id='status'>
<span class='mainWindow'>Main Window</span>
<span class='childWindow'>Child Window</span>
</div>
</body>
</html>
CSS:
#status
{
display:table;
width:100%;
height:500px;
border:1px solid black;
}
span
{
vertical-align:middle;
text-align:center;
margin:0 auto;
font-size:50px;
font-family:arial;
color:#ba3fa3;
display:none;
}
#status.main .mainWindow,
#status.child .childWindow
{
display:table-cell;
}
.mainWindow
{
background-color:#22d86e;
}
.childWindow
{
background-color:#70aeff;
}

(2021) You can use BroadcastChannel to communicate between tabs of the same origin.
For example, put the following at the top level of your js code, then test by opening 2 tabs:
const bc = new BroadcastChannel("my-awesome-site");
bc.onmessage = (event) => {
if (event.data === `Am I the first?`) {
bc.postMessage(`No you're not.`);
alert(`Another tab of this site just got opened`);
}
if (event.data === `No you're not.`) {
alert(`An instance of this site is already running`);
}
};
bc.postMessage(`Am I the first?`);

I know it is late, but maybe help someone
This snippet of code, will detect how many tabs are open and how many are active (visible) and if none of tabs is active, it will choose last opened tab, as active one.
This code will handle windows/tab crash too and it will refresh the count at crash.
Because localStorage is not supported on Stack Overflow currently, please test here.
<html>
<body>
Open in several tabs or windows
<div id="holder_element"></div>
<script type="text/javascript">
//localStorage.clear();
manage_crash();
//Create a windows ID for each windows that is oppened
var current_window_id = Date.now() + "";//convert to string
var time_period = 3000;//ms
//Check to see if PageVisibility API is supported or not
var PV_API = page_visibility_API_check();
/************************
** PAGE VISIBILITY API **
*************************/
function page_visibility_API_check ()
{
var page_visibility_API = false;
var visibility_change_handler = false;
if ('hidden' in document)
{
page_visibility_API = 'hidden';
visibility_change_handler = 'visibilitychange';
}
else
{
var prefixes = ['webkit','moz','ms','o'];
//loop over all the known prefixes
for (var i = 0; i < prefixes.length; i++){
if ((prefixes[i] + 'Hidden') in document)
{
page_visibility_API = prefixes[i] + 'Hidden';
visibility_change_handler = prefixes[i] + 'visibilitychange';
}
}
}
if (!page_visibility_API)
{
//PageVisibility API is not supported in this device
return page_visibility_API;
}
return {"hidden": page_visibility_API, "handler": visibility_change_handler};
}
if (PV_API)
{
document.addEventListener(PV_API.handler, function(){
//console.log("current_window_id", current_window_id, "document[PV_API.hidden]", document[PV_API.hidden]);
if (document[PV_API.hidden])
{
//windows is hidden now
remove_from_active_windows(current_window_id);
//skip_once = true;
}
else
{
//windows is visible now
//add_to_active_windows(current_window_id);
//skip_once = false;
check_current_window_status ();
}
}, false);
}
/********************************************
** ADD CURRENT WINDOW TO main_windows LIST **
*********************************************/
add_to_main_windows_list(current_window_id);
//update active_window to current window
localStorage.active_window = current_window_id;
/**************************************************************************
** REMOVE CURRENT WINDOWS FROM THE main_windows LIST ON CLOSE OR REFRESH **
***************************************************************************/
window.addEventListener('beforeunload', function ()
{
remove_from_main_windows_list(current_window_id);
});
/*****************************
** ADD TO main_windows LIST **
******************************/
function add_to_main_windows_list(window_id)
{
var temp_main_windows_list = get_main_windows_list();
var index = temp_main_windows_list.indexOf(window_id);
if (index < 0)
{
//this windows is not in the list currently
temp_main_windows_list.push(window_id);
}
localStorage.main_windows = temp_main_windows_list.join(",");
return temp_main_windows_list;
}
/**************************
** GET main_windows LIST **
***************************/
function get_main_windows_list()
{
var temp_main_windows_list = [];
if (localStorage.main_windows)
{
temp_main_windows_list = (localStorage.main_windows).split(",");
}
return temp_main_windows_list;
}
/**********************************************
** REMOVE WINDOWS FROM THE main_windows LIST **
***********************************************/
function remove_from_main_windows_list(window_id)
{
var temp_main_windows_list = [];
if (localStorage.main_windows)
{
temp_main_windows_list = (localStorage.main_windows).split(",");
}
var index = temp_main_windows_list.indexOf(window_id);
if (index > -1) {
temp_main_windows_list.splice(index, 1);
}
localStorage.main_windows = temp_main_windows_list.join(",");
//remove from active windows too
remove_from_active_windows(window_id);
return temp_main_windows_list;
}
/**************************
** GET active_windows LIST **
***************************/
function get_active_windows_list()
{
var temp_active_windows_list = [];
if (localStorage.actived_windows)
{
temp_active_windows_list = (localStorage.actived_windows).split(",");
}
return temp_active_windows_list;
}
/*************************************
** REMOVE FROM actived_windows LIST **
**************************************/
function remove_from_active_windows(window_id)
{
var temp_active_windows_list = get_active_windows_list();
var index = temp_active_windows_list.indexOf(window_id);
if (index > -1) {
temp_active_windows_list.splice(index, 1);
}
localStorage.actived_windows = temp_active_windows_list.join(",");
return temp_active_windows_list;
}
/********************************
** ADD TO actived_windows LIST **
*********************************/
function add_to_active_windows(window_id)
{
var temp_active_windows_list = get_active_windows_list();
var index = temp_active_windows_list.indexOf(window_id);
if (index < 0)
{
//this windows is not in active list currently
temp_active_windows_list.push(window_id);
}
localStorage.actived_windows = temp_active_windows_list.join(",");
return temp_active_windows_list;
}
/*****************
** MANAGE CRASH **
******************/
//If the last update didn't happened recently (more than time_period*2)
//we will clear saved localStorage's data and reload the page
function manage_crash()
{
if (localStorage.last_update)
{
if (parseInt(localStorage.last_update) + (time_period * 2) < Date.now())
{
//seems a crash came! who knows!?
//localStorage.clear();
localStorage.removeItem('main_windows');
localStorage.removeItem('actived_windows');
localStorage.removeItem('active_window');
localStorage.removeItem('last_update');
location.reload();
}
}
}
/********************************
** CHECK CURRENT WINDOW STATUS **
*********************************/
function check_current_window_status(test)
{
manage_crash();
if (PV_API)
{
var active_status = "Inactive";
var windows_list = get_main_windows_list();
var active_windows_list = get_active_windows_list();
if (windows_list.indexOf(localStorage.active_window) < 0)
{
//last actived windows is not alive anymore!
//remove_from_main_windows_list(localStorage.active_window);
//set the last added window, as active_window
localStorage.active_window = windows_list[windows_list.length - 1];
}
if (! document[PV_API.hidden])
{
//Window's page is visible
localStorage.active_window = current_window_id;
}
if (localStorage.active_window == current_window_id)
{
active_status = "Active";
}
if (active_status == "Active")
{
active_windows_list = add_to_active_windows(current_window_id);
}
else
{
active_windows_list = remove_from_active_windows(current_window_id);
}
console.log(test, active_windows_list);
var element_holder = document.getElementById("holder_element");
element_holder.insertAdjacentHTML("afterbegin", "<div>"+element_holder.childElementCount+") Current Windows is "+ active_status +" "+active_windows_list.length+" window(s) is visible and active of "+ windows_list.length +" windows</div>");
}
else
{
console.log("PageVisibility API is not supported :(");
//our INACTIVE pages, will remain INACTIVE forever, you need to make some action in this case!
}
localStorage.last_update = Date.now();
}
//check storage continuously
setInterval(function(){
check_current_window_status ();
}, time_period);
//initial check
check_current_window_status ();
</script>
</body>
</html>

content narration in web page, on tab press not going to speak anything if current task(speak anything) not completed

I am using articulate.js(http://www.jqueryscript.net/demo/Lightweight-jQuery-Based-Text-To-Speech-Engine-Articulate-js/) to read content from page and speak it. It is working fine, just not works if it is speaking something and I have press tab then it stops but not reads tab selected content.
some pre-define functions
<script>
function speak(obj) {
$(obj).articulate('speak');
};
function pause() {
$().articulate('pause');
};
function resume() {
$().articulate('resume');
};
function stop() {
$().articulate('stop');
};
</script>
what I have tried
<script>
$(document).ready(function() {
var counter = 0;
setTimeout(function(){
counter +=1;
if (counter == 1){
explode();
}
},1000);
function explode(){
//$('body').articulate('speak'); // Default for play whole content
$('h1').articulate('speak');
}
$('body').keyup(function (e) {
$().articulate('stop');
if (e.which == 9) { // on tab press start speaking selected element
var i=document.activeElement.id;
$('#'+i).articulate('pause').articulate('stop').articulate('speak');
}
else{ // trying to speak what key has been pressed except tab, but not working
var i=document.activeElement.id;
$('#'+i).val().articulate('speak');
}
});
});
</script>
I am also trying to make it audible(to speak keypress) on text box, which is not working

I have make some changes now it is working, but it has certain limitation like it not reads backspace, ctrl, space etc but speak a to z,1 to 0, very well. please improve it
<script>
$(document).ready(function() {
var counter = 0;
setTimeout(function(){
counter +=1;
if (counter == 1){
explode();
}
},1000);
function explode(){
//$('body').articulate('speak'); // Default for play whole content
$('h1').articulate('speak');
}
$('body').keyup(function (e) {
var speaking = $().articulate('isSpeaking');
var paused = $().articulate('isPaused');
// $().articulate('stop');
if (e.which == 9) {
if (speaking) {
$().articulate('pause');
$().articulate('stop');
}
var check =0;
setTimeout(function(){
check +=1;
if (check == 1){
comeback();
}
},1000);
function comeback() {
var i=document.activeElement.id;
$('#'+i).articulate('speak');
}
}
else{
var i=document.activeElement.id;
var m=0;
setTimeout(function () {
m+=1;
if(m==1){
magic();
}
},500);
function magic() {
var tempval=$('#'+i).val();
var lastChar = tempval.substr(tempval.length - 1);
var ht ='<div>'+lastChar+'</div>';
$(ht).articulate('speak');
}
}
});
});
</script>

AddEventListener function won't execute

The iFrameOn function runs on page load, and up until it is supposed to execute the iBold function is works fine. I've gone through and debugged as much as possible, and everything seems fine. When I output every variable to the console, the values are correct. It's just that one line (iBold(targetiFrame);) that won't run. I'm not sure what's going on.
function iFrameOn() {
var iFrames = document.querySelectorAll('form > iframe'); //Get all iframes in forms
var bolds = new Array(), italics = new Array(), underlines = new Array(), targetiFrame;
var getRT = document.getElementsByClassName('richText');
for (var rtIndex = 0; rtIndex < getRT.length;rtIndex++) { //Rich text event listeners
var rtid = getRT[rtIndex].id;
if (getRT[rtIndex].className == "richText bold") { //Bold text event listener
console.log('The id is: '+rtid);
bolds.push(rtid);
console.log('The bolds array contains: '+bolds);
} else if (getRT[rtIndex].className == 'richText underline') { //Underline text event listener
underlines.push(getRT[rtIndex]);
} else if (getRT[rtIndex].className == 'richText italic') { //Italic text event listener
italics.push(getRT[rtIndex]);
}
}
bolds.forEach(function(e, i, a) { //e = a[i]
console.log('e is '+e);
document.getElementById(e).addEventListener('click', function() {
console.log(e+' was clicked!');
targetiFrame = document.getElementById(e).getAttribute('data-pstid');
iBold(targetiFrame);
}, false);
});
}
function iBold(target) {
if (target == 0) {
document.getElementById('richTextField').contentDocument.execCommand('bold', false, null);
document.getElementById('richTextField').contentWindow.focus();
} else {
document.getElementById(target).contentDocument.execCommand('bold', false, null);
document.getElementById(target).contentWindow.focus();
}
}

I apparently had another iBold function in another js file

JS function that stops another JS function

I have two JS functions: a load() function that displays a progress bar and a kill () function that stops the execution of the load once the page is loaded.
Now when another page is loaded the progress bar is not displayed, knowing that the load function is called on every page.
Any hints on where the problem might be and if there is a way to fix it.
Here is my code:
<script type="text/javascript">
var count=0;
function load(i) {
j = parseInt(i);
document.getElementById("progressBar").style.display = "block";
count=count+1;
if (document.all) {
document.all.btn1.value=count+'%';
document.all.progressbar.pic1.width=2*count;
}
else {
document.getElementById("pic1").width=2*count;
document.getElementById("bar").width=count+'%';
}
if (count<100) {
setTimeout('load(j)',j);
}
if(count==100) {
document.getElementById("progressBar").style.display = "none";
count=0;
}
}
function kill(){
if (document.applets[0].isActive()) {
document.getElementById("progressBar").style.visibility = "hidden";
}
}
</script>
Thank you in advance !

In load() you're changing display to block, but in kill() you set visibility to hidden; you should set display to none instead, so it can properly be set to block again next time. Read about visibility.
Optimized code:
<script type="text/javascript">
var count = 0,
win = window,
doc = document,
progressBar = doc.getElementById("progressBar"),
t, j;
function load(i) {
j = parseInt(i);
progressBar.style.display = "block";
count++;
// no actual need to check if doc.all is available
// just select through id
doc.getElementById("pic1").style.width = 2*count;
doc.getElementById("bar").style.width = count+'%';
if (count < 100) {
t = win.setTimeout('load(j)',j);
} else {
progressBar.style.display = "none";
win.clearTimeout(t);
count = 0;
}
}
function kill(){
if (doc.applets[0].isActive()) {
progressBar.style.display = "none";
}
}
</script>

If you assign setTimeout to a variable, you can use clearTimeout on it to stop it.
E.g.
set the timeout with
t = setTimeout('load(j)',j);
then stop it with
clearTimeout(t); Let me know if that helps, and makes sense :)

How to make this code compatible with firefox browser

I have a question about multi browser compatibility. I want to use the event.target instead event.srcElement in the following code to make it work for firefox.
I have used target = event.target || event.srcElement. It is not working. Any help will be appreciated.
function jumptoPopupMenuItem(theMenuID)
{
if (event.srcElement.className == "RightClickMenuItems")
{
if (event.srcElement.getAttribute("url") != null)
{
var strParameters = "";
if (theMenuID == "mnuAppointmentMenu")
{
strParameters = "AppointmentNumber=" + m_strAppointmentTypeYearNumber;
}
else if (theMenuID == "mnuAvailableHourMenu")
{
strParameters = "PreFillLanguageID=" + m_nLanguageID;
strParameters = strParameters + "&PreFillInterpreterID=" + m_nInterpreterID;
strParameters = strParameters + "&PreFillDateOfService=" + m_dtDateOfService;
}
if (event.srcElement.getAttribute("target") != null)
{
var PopupWindow = window.open(
event.srcElement.url + strParameters,
event.srcElement.getAttribute("target"));
PopupWindow.focus();
}
else
{
window.location = event.srcElement.url;
}
}
hidePopupMenu(theMenuID);
}
}

Some standard ways to register event handlers with compatibility (very simplified code):
HTML:
<button onclick="eventHandlerFunc(event)" />
<!-- better to register as: -->
<button onclick="eventHandlerFunc.call(this,event)" />
JavaScript (addEventListener or attachEvent):
if (window.addEventListener) someElem.addEventListener("click",eventHandlerFunc,false);
else if (window.attachEvent) someElem.attachEvent("onclick",eventHandlerFunc);
JavaScript (element property):
someElem.onclick = eventHandlerFunc;
Where eventHandlerFunc() function defined as:
function eventHandlerFunc(event) { // or var eventHandlerFunc = function(event) {
event = event||window.event; // can be needed only for IE6-IE8
// because `event` parameter hide `event` global
// variable (`window.event`)
var target = event.target||event.srcElement
}
NOTE: If needed compatibility for this variable additional code must be added.
If then needed to use event variable (defined inside eventHandlerFunc() as parameter) inside other functions you must send it to these functions:
function eventHandlerFunc(event) {
event = event||window.event; // can be needed only for IE6-IE8
/*
...
*/
jumptoPopupMenuItem(event,theMenuID);
}
function jumptoPopupMenuItem(event,theMenuID) {
}