Detect if script has already loaded or not - javascript

It seems that helloworld.js gets loaded multiple times based on the number of times I click #load. I say this because when I look at Google Chromes Developer Tools Network tab, it shows helloworld.js as many times as I click #load.
$(document).ready(function() {
$("#load").click(function(){
$.getScript('helloworld.js', function() {
hello();
});
});
});
The hello() function looks like this:
function hello(){
alert("hello");
}
Is it possible to detect if helloworld.js has already loaded?
So if it hasn't loaded, load it, and if it has loaded, don't load it.
This is what Developer Tools currently shows me if I click the #load button 4 times:

Set a flag when file loaded successfully. If flag is set then skip the file loading again.
Try this code,
var isLoaded = 0; //Set the flag OFF
$(document).ready(function() {
$("#load").click(function(){
if(isLoaded){ //If flag is ON then return false
alert("File already loaded");
return false;
}
$.getScript('helloworld.js', function() {
isLoaded = 1; //Turn ON the flag
hello();
});
});
});

So why not only fire the event once like this:
$("#load").one("click", function() {
$load = $(this);
$.getScript('helloworld.js', function() {
hello();
// bind hello to the click event of load for subsequent calls
$load.on('click', hello);
});
});
That would prevent subsequent loads and avoids the use of a global

Another option is letting .getScript() run but let it take the script from browser's cache so you won't have it reloaded each and every time.
To achieve this, add such code:
$.ajaxSetup({
cache: true
});
This is taken from the documentation page.

You could create a helper function:
var getScript = (function() {
var loadedFiles = {};
return function(filename, callback) {
if(loadedFiles[filename]) {
callback();
} else {
$.getScript(filename, function() {
loadedFiles[filename] = true;
callback();
});
}
};
})();

Related

Turbolinks: How to stop running functions when you leave the page?

In my Rails 5.2.2 app I am using Turbolinks.
I have discovered that when I leave a page, the functions that were started continues.
I have organised my functions below a return statement that checks the body class. In my example below, if the body class is not foobar the functions below do not run.
// assets/javascripts/pages/foobar.js
var goLoop;
$(document).on("turbolinks:load", function() {
if (!$("body").hasClass("foobar")) {
return;
}
return goLoop();
});
goLoop = function() {
return setTimeout((function() {
console.log("Hello");
return goLoop();
}), 1000);
};
First time I visit the page, the goLoop function is triggered.
When I follow a link away from the page, the function runs. If I had not used Turbolinks, this would not have happened.
If I follow another link back to the page, the function is triggered again, so now it runs twice.
How can I avoid this, without disabling Turbolinks?
Use the turbolinks:before-cache to teardown your timeout using clearTimeout. You will need to keep a reference of the current timeout ID. So your solution might look like:
var goLoop;
var timeout;
$(document).on("turbolinks:load", function() {
if (!$("body").hasClass("foobar")) {
return;
}
return goLoop();
});
goLoop = function() {
return timeout = setTimeout((function() {
console.log("Hello");
return goLoop();
}), 1000);
};
$(document).on("turbolinks:before-render", function() {
clearTimeout(timeout);
});
You can use PageVisibilityAPI to see is current page active or not.
and for the loop issue, you should check whether it's exist or not then run timeout function.

how to get jquery to run repeatedly

I currently have a piece of jquery code that looks for a specific URL (with an anchor at the end) and runs a function if it has a match. The code only runs once, if this is the first URL loaded. Is it possible to have the following code running until it has a match?
$(document).ready(function(){
var url = "https://s3-eu-west-1.amazonaws.com/datahealthcheck16-test/index.html#backup-section-3";
$(function(){
if (location.href==url){
paintLine();
}
})
});
It only runs the first time, because changing the hash does not fire the DOM ready handler again, it does however fire the hashchange event.
$(window).on('hashchange', function() {
if ( window.location.hash === '#backup-section-3' ) {
paintLine();
}
}).trigger('hashchange'); // fire on first load as well
Note that the window is always available, and does not need a DOM ready handler
you can use setTimeout() function to run your function, for example every second:
$(document).ready(function(){
var url = "https://s3-eu-west-1.amazonaws.com/datahealthcheck16-test/index.html#backup-section-3";
function test() {
if (location.href == url) {
paintLine();
} else {
setTimeout(test, 1000);
}
}
test();
});
but what is your idea, behind your code? I sure there is more convenient ways to do your task.
using adeneo's answer:
here is what matches your code:
$(document).ready(function(){
var url = "https://s3-eu-west-1.amazonaws.com/datahealthcheck16-test/index.html#backup-section-3";
$(function(){
if (location.href==url){
paintLine();
}
});
$(window).on('hashchange', function() {
if ( location.href == url ) {
paintLine();
}
});
});

How to start javascript setinterval once cleared?

I have a setinterval that runes every 5 seconds. this works fine on page load.
I have the following scenarios:
Load page with interval (WORKS)
press button and load new content and stopp interval(WORKS)
Once the new content is no longer desiered, dissmiss it, return to first content and start interval again(DOES NOT WORK)
I have saftys suchs as events for window.blur that also stops the interval so that the browser does not commponsate for all the missing intervals if i would change tabs or something. Keep in mind that step 3 did not work BUT if i would after step 3 change a tab and then return to my original page(execute blur) the interval would start working again.
NOTE all content loading here exept page load is done with ajax calls.
My code:
initializing:
$.automation.worker.bindIntervalEvent("#TanksContent", "/Tank/GetTanks", function() {
$.automation.tanks.tableInit();
});
binding function:
bindIntervalEvent: function (target, url, callback) {
$(window)
.on("focus.mine",
function() {
$.automation.worker.setUpdateInterval(target, url, callback);
})
.on("blur",
function() {
$.automation.worker.stopUpdateInterval();
}).trigger("focus.mine");
}
interval function:
setUpdateInterval: function (target, url, callback) {
if ($.automation.globals.globalInterval.value.length === 0) {
$.automation.globals.globalInterval.value.push(window.setInterval(
function () {
var options = {
loadTarget: target
}
$.automation.worker.getView(url,
function() {
if (callback)
callback();
},
options);
},
5000));
}
}
the function that stops the interval:
stopUpdateInterval: function () {
if ($.automation.globals.globalInterval.value.length === 0)
return;
console.log("deleting");
for (var i = 0; i <= $.automation.globals.globalInterval.value.length; i++) {
window.clearInterval($.automation.globals.globalInterval.value[i])
$.automation.globals.globalInterval.value.splice(i, 1);
console.log($.automation.globals.globalInterval.value.length);
}
}
when stopping the interval i also remove the window bindings:
unBindIntervalEvent: function() {
$(window).off("focus.mine");
$(window).unbind("blur");
}
Back to step 3:
My sucess method in the callback to my getviewfunction is identical to what i execute in the beginning
code:
$(".updatelatest")
.on("click",
function () {
var _this = $(this);
var options = {
loadTarget:"#TanksContent"
}
$.automation.worker.getView("/Tank/GetTanks",
function (data) {
$(_this).switchClass("col-md-5", "col-md-1", 1000, function() {
$(_this).addClass("hidden");
$(".search").switchClass("col-md-5", "col-md-12", 1000, "easeInOutQuad");
})
$.automation.tanks.tableInit();
$.automation.worker.bindIntervalEvent("#TanksContent", "/Tank/GetTanks", function () {
$.automation.tanks.tableInit();
});
$(window).trigger("blur");
}, options);
});
but this does not start the interval. it is clearly initialized since it works when window.blur is executed for example when I change tab but for some reason this is not working beyond that.
i tried triggering the windows blur event and nothing happened, i tried triggering my custom window event "focuse.mine" but nothing happens.
I did not notice this while developing since I had firebug open and every time i checked scripts or css or the console the blur function was executed so I assumed that my code worked as intended but now that it is deployed I notice this.
My head is pounding beyond reason and I can't for figure out where I have gone wrong.
Well this was a fun one. I simply found that when calling the setUpdateInterval(); function directly it gave me the desiered result.
I realized that the reason I had them split like I did was becaouse of the blur event. "Focus.mine" is triggered to start the inteval again ocne a user comes back to the page.

Sequencing two action on a button click

Problem: I have a asp.net button and on click of that I am displaying another window using window.open() at the client side using <script></script>
"I actually, need a popup (alert message) to be displayed on my parent page where my button is located once the user closes the child window."
Couple of things I tried are as follows:
I tried using setTimeOut() to have a time out for some milliseconds. This does not work as the control is not waiting until the time out is complete. It just proceeds to execute next set of code.
I tried using setInterval() but for some reason it is not working for me. Below is the code snippet of that:
$(document).ready(function () {
$('#<%=btnClick.ClientID%>').bind('click', function () {
var newWindow = window.open("http://www.google.com/", "google", 'resizable=1,width=900,height=800,scrollbars=1', '_blank');
newWindow.moveTo(0, 0);
var test = setInterval(function (e) {
if (newWindow.closed) {
alert("HEYY");
clearInterval(test);
__doPostBack("<%= btnClick.UniqueID %>", "");
}
else {
e.preventDefault();
}
}, 5000);
});
});
.
I also tried making an ajax call to open the new window and make it async : false, it again did not help me.
Bring your window and timer variable out of scope of the event handler. You need to do a polling i.e. periodically keep on checking if the windows has been closed. Using setInterval to do a polling will do the job.
var newWin, pollTimer;
$('#btnId').bind('click', function () {
newWin = window.open("...", "...", "");
pollTimer = window.setInterval(function() {
if (newWin.closed) {
window.clearInterval(pollTimer);
callCodeWhenPopupCloses();
}
}, 5000);
});
function callCodeWhenPopupCloses() {
alert("Popup closed.");
...
}

NightwatchJS .waitForElementPresent abortOnFailure not working

I'm using NightwatchJS with NodeJS: http://nightwatchjs.org/api
I have a modal dialog, which may or may not appear. It has a #close_button that needs to be clicked (if the modal does appear) to continue.
I set the abortOnFailure parameter of waitForElementPresent to false so the script continues if the modal does not appear. However I can't get it to work.
Any suggestions?
module.exports = {
"Test" : function (browser) {
browser
.url("http://domain.com/")
.waitForElementPresent('#close_button', 5000, false, function() {
this.click('#close_button')
})
.setValue('#username', 'test#email.com')
//more code here
.end(); //does end() go here or inside .waitForElementPresent() above?
}
}
abortOnFailure works fine, however waitForElementPresent has a bug now in which the callback you passed it's not called in the correct context. That will be fixed.
In the mean time you can write your test like this, with placing the click outside, which is the same thing and looks cleaner:
module.exports = {
"Test" : function (browser) {
browser
.url("http://domain.com/")
.waitForElementPresent('#close_button', 5000, false)
.click('#close_button')
.setValue('#username', 'test#email.com')
//more code here
.end(); // end() goes here
}
}
I ran into something similar, I was waiting for an iframe to be present. I created a function to actually close it:
pageObject function:
Home.prototype.closeIframe = function(browser) {
var self = this;
console.log('Checking for iframe');
this.browser
.isVisible(iframeSelectors.iframe, function(result) {
if (result.value === true) {
self.browser
.log('iframe visible')
.frame(iframeSelectors.name)
.waitForElementVisible(iframeSelectors.closeLink)
.click(iframeSelectors.closeLink)
.assert.elementNotPresent(iframeSelectors.iframe)
.frame(null)
.pause(2000); //allow for proper frame switching
} else {
console.log('iframe is not visible');
}
});
return this;
In my test I wait for the page to fully load before executing the above function.

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