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javascript DOM object (window) extended property is null on page reload after being idle

I have a custom extended property attached to the window object in JavaScript as follows:
Community.js
(function (window, document, $) {
'use strict';
var containerScrollPositionOnHideList = [];
var scrollToTopOnShowContainerList = [];
var userProfileInfo = {};
window.Community = $.extend({
//init
init: function () {
var Site = window.Site;
Site.run();
this.enableHideShowEventTrigger();
},
setUserInfo: function (userObj) {
if (UtilModule.allowDebug) { debugger; }
window.localStorage.setItem('userInfo', JSON.stringify(userObj));
var d = new $.Deferred();
$.when(this.initUserProfile(userObj.UserId)).done(function () {
d.resolve("ok");
});
},
getUserInfo: function () {
var userJson = window.localStorage.getItem('userInfo');
var userObj = JSON.parse(userJson);
return userObj;
},
})(window, document, jQuery);
The problem is that this extension property window.Community is null in certian scenarios when i refresh the page which i am going to describe below along with flow of code.
and here is a module in JavaScript to force reload scripts even if they are cached every time the page is refreshed as my code heavily depends on javascript calls so I just enabled it to make sure while I am still writing the code page reloads every time, the code is below as follows:
Util.js
var UtilModule = (function () {
var allowDebug = false;
var currentVersion = 0;
var properlyLoadScript = function (scriptPath, callBackAfterLoadScript) {
//get the number of `<script>` elements that have the correct `src` attribute
//debugger;
var d = $.Deferred();
$('script').each(function () {
console.log($(this).attr('src'));
});
if (typeof window.Community == 'undefined') {
//debugger;
console.log('community was undefined till this point');
//the flag was not found, so the code has not run
$.when(forceReloadScript(scriptPath)).done(function () {
callBackAfterLoadScript();
d.resolve("ok");
});
}
else {
console.log('Community loaded already and running now : ' + scriptPath);
callBackAfterLoadScript();
}
return d.promise();
};
var forceReloadScript = function (scriptPath) {
if (UtilModule.allowDebug) { debugger; }
var d = $.Deferred();
initCurrentVersion();
var JSLink = scriptPath + "?version=" + currentVersion;
var JSElement = document.createElement('script');
JSElement.src = JSLink;
JSElement.onload = customCallBack;
document.getElementsByTagName('head')[0].appendChild(JSElement);
function customCallBack() {
d.resolve("ok");
}
return d.promise();
};
var enableDebugger = function () {
allowDebug = true;
};
var disableDebugger = function () {
allowDebug = false;
};
var debugBreakPoint = function () {
if (allowDebug) {
}
};
var initCurrentVersion = function () {
if (currentVersion == 0) {
var dt = new Date();
var ttime = dt.getTime();
currentVersion = ttime;
}
};
var getCurrentVersion = function () {
return currentVersion;
};
return {
forceReloadScript,
properlyLoadScript,
enableDebugger,
disableDebugger,
debugBreakPoint,
allowDebug,
getCurrentVersion
};
})();
Note: I have made deferred objects to resolve only when the JSElement.onload has been called successfully. This step was taken just for testing purpose to make sure that I am not missing something before reaching a point to call the method where I am getting an error.
After that the code where I load scripts using UtilModule in my layout file look like as below:
_Layout.cshtml
<script src = "~/Scripts/Application/Modules/Util.js" ></script>
<script>
$.when(
UtilModule.properlyLoadScript('/Scripts/Application/Community.js', () => {
// Community.init() was supposed to be called here but i was still getting the error so i implemented this using promise that is returned from properlyLoadScript and call Community.init() further in .done callback to make sure that script is properly loading till this point.
//window.Community.init();
})
).done(function() {
window.Community.init();
});
</script>
#RenderSection("scripts", required: false)
Now coming to my main file where My index file is executing having (_layout.chsmtl) as parent layout
is
Index.cshtml
#{
ViewBag.Title = "My Blog";
Layout = "~/Views/Shared/_Layout.cshtml";
}
<article id="BlogPage" style="margin: 5px;">
</article>
#section scripts{
<script type="text/javascript">
$(document).ready(function () {
$.when(UtilModule.properlyLoadScript('/Scripts/Application/Modules/Blog.js', () => {
})).done(function () {
BlogModule.init();
});
});
//});
</script>
}
from what I know is that #section scripts is executed only once all the scripts in the layout page are loaded first so seems like a safe place to initialize the code which is dependent on some script in _Layout.HTML file and further enclosed with $(document).ready() for testing just to make sure that this script loads after everything else is loaded already.
Note: I am running all this code in in-cognito mode in chrome so nothing is cached while this code is running
now my Blog.js file looks like as below
var BlogModule = (function () {
var moduleReference = this;
var PageId = "#BlogPage ";
var currentUser;
var BlogPostList = [];
var blogPostInfo = {};
//init
var init = function () {
if (UtilModule.allowDebug) { debugger; }
//This is where the problem happens
console.log(window.Community);
console.log(window.Community.getUserInfo());
currentUser = window.Community.getUserInfo();
initBlogInformation();
//window.Community.registerModule(BlogModule);
if (Object.keys(window.Community.getUserProfileObject()) <= 0) {
$.when(window.Community.initUserProfile(currentUser.UserId)).then(function () {
$.when(initBlogInformation()).done(function () {
//debugger;
console.log(BlogPostList);
window.WidgetManager.populateWidget(PageId, moduleReference);
loadBlogPostWidget();
loadBlogViewWidget();
loadBlogCommentsWidget();
});
});
}
else {
$.when(initBlogInformation()).done(function () {
window.WidgetManager.populateWidget(PageId, moduleReference);
loadBlogPostWidget();
loadBlogViewWidget();
loadBlogCommentsWidget();
});
}
};
var loadBlogIndexMenuWidget = function () {
if (UtilModule.allowDebug) { debugger; }
};
var loadBlogPostWidget = function () {
var widgetOptions = {};
widgetOptions.type = "BlogPostWidget";
widgetOptions.container = PageId + "#BlogPostWidgetContainer";
var settings = {};
settings.UserId = 1;
widgetOptions.settings = settings;
window.WidgetManager.loadWidget(widgetOptions);
}
var loadBlogViewWidget = function () {
var widgetOptions = {};
widgetOptions.type = "BlogViewWidget";
widgetOptions.container = PageId + "#BlogViewWidgetContainer";
var settings = {};
settings.UserId = 1;
widgetOptions.settings = settings;
window.WidgetManager.loadWidget(widgetOptions);
};
var loadBlogCommentsWidget = function () {
var widgetOptions = {};
widgetOptions.type = "BlogCommentsWidget";
widgetOptions.container = PageId + "#BlogCommentsWidgetContainer";
var settings = {};
settings.UserId = 1;
widgetOptions.settings = settings;
window.WidgetManager.loadWidget(widgetOptions);
};
var initBlogList = function () {
$.when(getBlogPosts()).then(function (results) {
if (UtilModule.allowDebug) { debugger; }
BlogPostList = results.Record;
console.log(BlogPostList);
});
};
var getBlogPosts = function () {
if (UtilModule.allowDebug) { debugger; }
var d = new $.Deferred();
var uri = '/Blog/GetBlogPosts?userId=' + currentUser.UserId;
$.post(uri).done(function (returnData) {
if (UtilModule.allowDebug) { debugger; }
if (returnData.Status == "OK") {
BlogPostList = returnData.Record;
BlogPostList.map(x => {
if (UtilModule.allowDebug) { debugger; }
x.UserName = window.Community.getUserProfileObject().UserName;
if (x.Comments != null) {
x.CommentsObject = JSON.parse(x.Comments);
x.CommentsCount = x.CommentsObject.length;
}
});
console.log(returnData.Record);
d.resolve("ok");
} else {
window.Community.showNotification("Error", returnData.Record, "error");
d.resolve("error");
}
});
return d.promise();
};
var initBlogInformation = function () {
//debugger;
var d = $.Deferred();
getBlogPosts().then(getBlogModelTemplate()).then(function () {
d.resolve("ok");
});
return d.promise();
};
//Get Blog Model
var getBlogModelTemplate = function () {
var d = new $.Deferred();
var uri = '/Blog/GetBlogModel';
$.post(uri).done(function (returnData) {
blogPostInfo = returnData.Record;
d.resolve("ok");
});
return d.promise();
};
return {
init: init,
};
})();
The error I have highlighted below
so the problem is in init function of BlogModule which is BlogModule.init() the page is idle for too long and I reload it I get the following error:
cannot call
window.Community.getUserInfo() of undefined implying that community is undefied
after couple of refreshes its fine and the issue doesn't happen unless I change reasonable portion of code for js files to be recompiled again by browser or the browser is idle for too long and I am not able to understand what is triggering this issue.
below is log from console
p.s. error occurs more repeatedly if i refresh page with f5 but happens rarely if i refresh page with ctrl + f5
Please any help would be of great value

Answering my own question, took a while to figure it out but it was a small mistake on my end just fixing the following function in Util.js fixed it for me
var properlyLoadScript = function(scriptPath, callBackAfterLoadScript) {
//get the number of `<script>` elements that have the correct `src` attribute
//debugger;
var d = $.Deferred();
$('script').each(function() {
console.log($(this).attr('src'));
});
if (typeof window.Community == 'undefined') {
//debugger;
console.log('community was undefined till this point');
//the flag was not found, so the code has not run
$.when(forceReloadScript('/Scripts/Application/Community.js')).done(function() {
//debugger;
$.when(forceReloadScript(scriptPath)).done(function() {
callBackAfterLoadScript();
});
d.resolve("ok");
});
} else {
console.log('Community loaded already and running now : ' + scriptPath);
$.when(forceReloadScript(scriptPath)).done(function() {
callBackAfterLoadScript();
});
}
return d.promise();
};

Chrome Extensions, scope the local variable in.in.inside a function (from backgound.js )and use it globally (or in popup.js).

Recently I want to start a project by piggyback someone's extension. I want to scope one of the image source (local variable, a base64 url) and then photo recognize it on the popup page. I keep getting error "imgb64.replace is not a function" or "imgb64" not defined.
like my title said, I want to scope the local variable in.in.inside a function (from backgound.js )and use it globally (or in popup.js). very new to this, please help guys.
// this is popup.js
chrome.runtime.getBackgroundPage(function(bg) {
bg.capture(window);
});
/// what I did
function img_find() {
var imgs = document.getElementsByTagName("img");
var imgSrcs = [];
for (var i = 0; i < imgs.length; i++) {
imgSrcs.push(imgs[i].src);
}
return imgSrcs;
}
var imgb64 = img_find();
try {
const app = new Clarifai.App({
apiKey: 'mykey'
});
}
catch(err) {
alert("Need a valid API Key!");
throw "Invalid API Key";
}
// Checks for valid image type
function validFile(imageName) {
var lowerImageName = imageName.toLowerCase();
return lowerImageName.search(/jpg|png|bmp|tiff/gi) != -1;
}
var imageDetails = imgb64.replace(/^data:image\/(.*);base64,/, '');
console.log(imageDetails)
app.models.predict("e466caa0619f444ab97497640cefc4dc", {base64:
imageDetails}).then(
function(response) {
// do something with response
},
function(err) {
// there was an error
}
);
/// end what I did
below is background.js, I think what I need is the local var img.src, thats all.
function capture(popup) {
function callOnLoad(func) {
popup.addEventListener("load", func);
if (popup.document.readyState === "complete") {
func();
}
}
crxCS.insert(null, { file: "capture.js" }, function() {
crxCS.callA(null, "get", function(result) {
var scrShot, zm, bufCav, bufCavCtx;
function mkImgList() {
for (var i = 0; i < result.vidShots.length; i++) {
var img = new popup.Image();
img.onload = function() {
this.style.height = this.naturalHeight /
(this.naturalWidth / 400) + "px";
};
if (result.vidShots[i].constructor === String) {
img.src = result.vidShots[i];
} else {
bufCav.width = result.vidShots[i].width * zm;
bufCav.height = result.vidShots[i].height * zm;
bufCavCtx.drawImage(scrShot, -result.vidShots[i].left *
zm, -result.vidShots[i].top * zm);
img.src = bufCav.toDataURL('image/png');
////// maybe clarifai here ?
////end clarifai
}
popup.document.body.appendChild(img);
}
popup.onclick = function(mouseEvent) {
if (mouseEvent.target.tagName === "IMG") {
chrome.downloads.download({ url: mouseEvent.target.src,
saveAs: true, filename: "chrome_video_capture_" + (new Date()).getTime() +
".png" });
}
};
popup.onunload = function(mouseEvent) {
crxCS.callA(null, "rcy");
};
} /// end mkImgList
if (result.needScrShot) {
bufCav = popup.document.createElement("canvas");
bufCavCtx = bufCav.getContext("2d");
chrome.tabs.captureVisibleTab({ format: "png" },
function(dataUrl) {
scrShot = new Image();
scrShot.onload = function() {
chrome.tabs.getZoom(function(zoomFactor) {
zm = zoomFactor;
callOnLoad(function() {
mkImgList(zoomFactor);
});
});
};
scrShot.src = dataUrl;
});
} else if (result.vidShots.length) {
callOnLoad(mkImgList);
} else {
popup.document.body.appendChild(notFound);
}
}); // end crxCS.callA
}); // end crxCS.insert
} // end capture
Please help guys. :)

redeclare javascript function

I hope that somebody can help me.
I want to redeclare js function by extension.
For example, there is the basic js function on website:
function foo(){
..something here..
}
i want to redeclare it by own function with the same name. how it will be easiest to do?
edit 1. i'll try to explain better.
there is a native code in website:
Notifier = {
debug: false,
init: function (options) {
curNotifier = extend({
q_events: [],
q_shown: [],
q_closed: [],
q_max: 3,
q_idle_max: 5,
done_events: {},
addQueues: curNotifier.addQueues || {},
recvClbks: curNotifier.recvClbks || {},
error_timeout: 1,
sound: new Sound('mp3/bb1'),
sound_im: new Sound('mp3/bb2')
}, options);
if (!this.initFrameTransport() && !this.initFlashTransport(options)) {
return false;
}
this.initIdleMan();
if (!(curNotifier.cont = ge('notifiers_wrap'))) {
bodyNode.insertBefore(curNotifier.cont = ce('div', {id: 'notifiers_wrap', className: 'fixed'}), ge('page_wrap'));
}
},
destroy: function () {
Notifier.hideAllEvents();
curNotifier.idle_manager.stop();
curNotifier = {};
re('notifiers_wrap');
re('queue_transport_wrap');
},
reinit: function () {
ajax.post('notifier.php?act=a_get_params', {}, {
onDone: function (options) {
if (options) {
curNotifier.error_timeout = 1;
this.init(options);
} else {
curNotifier.error_timeout = curNotifier.error_timeout || 1;
setTimeout(this.reinit.bind(this), curNotifier.error_timeout * 1000);
if (curNotifier.error_timeout < 256) {
curNotifier.error_timeout *= 2;
}
}
}.bind(this),
onFail: function () {
curNotifier.error_timeout = curNotifier.error_timeout || 1;
setTimeout(this.reinit.bind(this), curNotifier.error_timeout * 1000);
if (curNotifier.error_timeout < 256) {
curNotifier.error_timeout *= 2;
}
return true;
}.bind(this)
});
}
}
and function Sound
function Sound(filename) {
var audioObjSupport = false, audioTagSupport = false, self = this, ext;
if (!filename) throw 'Undefined filename';
try {
var audioObj = ce('audio');
audioObjSupport = !!(audioObj.canPlayType);
if (('no' != audioObj.canPlayType('audio/mpeg')) && ('' != audioObj.canPlayType('audio/mpeg')))
ext = '.mp3?1';
else if (('no' != audioObj.canPlayType('audio/ogg; codecs="vorbis"')) && ('' != audioObj.canPlayType('audio/ogg; codecs="vorbis"')))
ext = '.ogg?1';
else
audioObjSupport = false;
} catch (e) {}
// audioObjSupport = false;
if (audioObjSupport) {
audioObj.src = filename + ext;
var ended = false;
audioObj.addEventListener('ended', function(){ended = true;}, true);
audioObj.load();
this.playSound = function() {
if (ended) {
audioObj.load();
}
audioObj.play();
ended = false;
};
this.pauseSound = function() {
audioObj.pause();
};
} else {
cur.__sound_guid = cur.__sound_guid || 0;
var wrap = ge('flash_sounds_wrap') || utilsNode.appendChild(ce('span', {id: 'flash_sounds_wrap'})),
guid = 'flash_sound_' + (cur.__sound_guid++);
var opts = {
url: '/swf/audio_lite.swf?4',
id: guid
}
var params = {
swliveconnect: 'true',
allowscriptaccess: 'always',
wmode: 'opaque'
}
if (renderFlash(wrap, opts, params, {})) {
var swfObj = browser.msie ? window[guid] : document[guid],
inited = false,
checkLoadInt = setInterval(function () {
if (swfObj && swfObj.paused) {
try {
swfObj.setVolume(1);
swfObj.loadAudio(filename + ext);
swfObj.pauseAudio();
} catch (e) {debugLog(e);}
}
inited = true;
clearInterval(checkLoadInt);
}, 300);
self.playSound = function() {
if (!inited) return;
swfObj.playAudio(0);
};
self.pauseSound = function() {
if (!inited) return;
swfObj.pauseAudio();
};
}
}
}
Sound.prototype = {
play: function() {
try {this.playSound();} catch(e){}
},
pause: function() {
try {this.pauseSound();} catch(e){}
}
};
when i try to add injection with redeclaration function Sound it doesn't work.
if i create my own function, for example, xSound and сall it this way:
cur.sound = new xSound('mp3/bb1');
it's working.

You can do it like this, for example:
foo = function(args) {
// method body...
}
JavaScript is a programming language where functions are first-class citizens so you can manipulate them like other types.
UPDATE:
Make sure that this piece of code actually does the redefinition and not the first definition. (thanks to #jmort253)

function foo(){
// ..something else here..
}

Remember that an extension's Content Script code and the webpage code run in different execution contexts.
So if you want to redefine a function that exists in the webpage context, you'll have to inject your code into the webpage. Take a look at this answer by Rob W for different methods of doing that:
Insert code into the page context using a content script

jquery conflict with js script

welcome all ,
i have a problem with my images slider , it runs successfuly until poll script excuted then it stops , tried to combine both scripts didn't work also tried to use noConflict but in stops both of them .
this is the slider
(function ($) {
$.fn.s3Slider = function (vars) {
var element = this;
var timeOut = (vars.timeOut != undefined) ? vars.timeOut : 4000;
var current = null;
var timeOutFn = null;
var faderStat = true;
var mOver = false;
var items = $("#sliderContent .sliderImage");
var itemsSpan = $("#sliderContent .sliderImage span");
items.each(function (i) {
$(items[i]).mouseover(function () {
mOver = true
});
$(items[i]).mouseout(function () {
mOver = false;
fadeElement(true)
})
});
var fadeElement = function (isMouseOut) {
var thisTimeOut = (isMouseOut) ? (timeOut / 2) : timeOut;
thisTimeOut = (faderStat) ? 10 : thisTimeOut;
if (items.length > 0) {
timeOutFn = setTimeout(makeSlider, thisTimeOut)
} else {
console.log("Poof..")
}
};
var makeSlider = function () {
current = (current != null) ? current : items[(items.length - 1)];
var currNo = jQuery.inArray(current, items) + 1;
currNo = (currNo == items.length) ? 0 : (currNo - 1);
var newMargin = $(element).width() * currNo;
if (faderStat == true) {
if (!mOver) {
$(items[currNo]).fadeIn((timeOut / 6), function () {
if ($(itemsSpan[currNo]).css("bottom") == 0) {
$(itemsSpan[currNo]).slideUp((timeOut / 6), function () {
faderStat = false;
current = items[currNo];
if (!mOver) {
fadeElement(false)
}
})
} else {
$(itemsSpan[currNo]).slideDown((timeOut / 6), function () {
faderStat = false;
current = items[currNo];
if (!mOver) {
fadeElement(false)
}
})
}
})
}
} else {
if (!mOver) {
if ($(itemsSpan[currNo]).css("bottom") == 0) {
$(itemsSpan[currNo]).slideDown((timeOut / 6), function () {
$(items[currNo]).fadeOut((timeOut / 6), function () {
faderStat = true;
current = items[(currNo + 1)];
if (!mOver) {
fadeElement(false)
}
})
})
} else {
$(itemsSpan[currNo]).slideUp((timeOut / 6), function () {
$(items[currNo]).fadeOut((timeOut / 6), function () {
faderStat = true;
current = items[(currNo + 1)];
if (!mOver) {
fadeElement(false)
}
})
})
}
}
}
};
makeSlider()
}
})(jQuery);
and this is the poll script
window.onload = function() {
$(".sidePollCon").load("ar_poll.html", function(r, s, xhr) {
if (s == "error") {
$(".sidePollCon").load("poll.html");
} else {
$(".vote_booroo").html("صوت الان");
$(".viewresults").html("شاهد النتيجة");
$("fieldset p").html("");
$(".results_booroo p").html("");
$(".result_booroo").attr("src", "../images/poll_color.jpg");
}
});
};

One potential problem could be the window.onload assignment. It is very prone to conflict.
Every time you do window.onload = the previous assignemnt will be overridden. See demo here:
The output shows that the first window.onload assignment never gets called, while the jQuery alternative does get called.
jQuery.noConflict does little in this regard. All it does is to prevent override the $ symbol so that another lib can use it.
So if you are also using the window.onload event to invoke the slider, then you have conflict. You can easily solve this problem by using the jquery format:
$(window).load(function() {
...
});
However usually you would tie the event to $(document).load(function(){...}); or in short form: $(function(){...}).
So for your poll that would be:
$(function(){
$(".sidePollCon").load("ar_poll.html", function(r, s, xhr) {
if (s == "error") {
$(".sidePollCon").load("poll.html");
} else {
$(".vote_booroo").html("صوت الان");
$(".viewresults").html("شاهد النتيجة");
$("fieldset p").html("");
$(".results_booroo p").html("");
$(".result_booroo").attr("src", "../images/poll_color.jpg");
}
});
});
Hope that helps.

resolving conflicts in jquery (possibly with another JS library .. like script.aculo.us) can be resolved using noconflict()
http://api.jquery.com/jQuery.noConflict/
$.noConflict();
but make sure that u have no error in your javascript code itself. use firebug and
console.log('') to test your script.

Problem with jquery inside OOP function

Hello I'm trying to get value of hidden element in my OOP function. Here is code:
var refreshTimeout;
var rms = new RMS();
rms.refresh();
function RMS() {
this.refresh = function(){
alert($("#ids").val());
$.post(refreshUrl, {ids: $("#ids").val()}, function(response){
var result = $.parseJSON(response);
if (result != null) {
$("#rms").attr("value", result.rms);
}
refreshTimeout = setTimeout(function() { rms.refresh(); }, 2000);
});
}
}
The problem is that $("#ids").val() works in firebug console but not inside rms.refresh()...
What I'm doing wrong?

Your invocation of $('#ids').val() looks fine, so long as the DOM is loaded at this point (i.e. inside a $(document).ready() block).
Your timer function looks a little suspect, though. You're referring to rms which is in the outer scope, when you should be referring to whatever the current object is.
Similarly your timer-related values should be properly encapsulated inside the class, since otherwise you can't have more than one instance.
// class definition - can be loaded anywhere
var RMS = function(ids, rms) {
var self = this;
var timer = null;
var delay = 2000;
this.refresh = function() {
$.post(refreshUrl, {ids: $(ids).val()},
function(response) {
var result = $.parseJSON(response);
if (result != null) {
$(rms).attr("value", result.rms);
}
timer = setTimeout(function() {
self.refresh();
}, delay);
}
);
};
};
// invocation deferred until the DOM is ready
$(document).ready(function() {
var rms = new RMS('#ids', '#rms');
rms.refresh();
});

Try this code:
$(document).ready(function(){
var refreshTimeout,
rms = new RMS();
rms.refresh();
function RMS() {
this.refresh = function(){
$.post(refreshUrl, {ids: $('#ids').val()}, function(response){
if (typeof(response) != 'undefined') {
$('#rms').attr('value', response.rms);
}
refreshTimeout = setTimeout(function() { rms.refresh(); }, 2000);
}, 'json');
}
}
});