I have a plugin that tells me if an element is visible in the viewport with $('#element').visible() (set to true when visible).
Now I want to create a function that I scroll down a page and load new content with ajax. I have this so far:
window.onscroll = function() {
console.log($('#ele').visible());
if ($('#ele').visible()) {
//ajax call comes here
}
};
As soon as I see the element my log shows true:
I don't have problems implementing the ajax-request now, but shouldn't I block this function to occur only once? How could I prevent that a new element that already has been loaded to load again (prevent using ajax again)?
I thought of using a boolean-variable, but my problem is that I don't know how to implement that because if I set a variable, how would the browser know it's value? Because on every move of my mousewheel it cant remember what that variable's value was?
EDIT:
I tried the code of Ismail and it never reaches the ajax call (alert won't show).
window.onscroll = function() {
var ajaxExecuted = false;
var ele = $('#load_more').visible();
console.log(ele);
return function() {
if (ajaxExecuted) return;
if (ele) {
alert("OK");
var ajaxArray;
ajaxArray = { page: 2 }
ajaxLoadContent(ajaxArray, "load_more", "ajax_load");
ajaxExecuted = true;
}
}
};
You can use this:
window.onscroll = (function() {
var ajaxExecuted = false;
return function() {
if(ajaxExecuted) return;
if ($('#ele').visible()) {
$.ajax({...}).success(function() {
//Your code here;
ajaxExecuted = true;
});
}
}
})();
One easy solution: set a boolean to true when the element first becomes visible and set it to false when it stops being visible. Only fire the request if those states mismatch (i.e. if it's visible but the boolean is false - that means it's the first time you've seen the window. You'd then set the bool afterwards so it won't fire off anymore until it disappears and reappears again).
Related
Here's the problem. I'm making a callback to the server that receives an MVC partial page. It's been working great, it calls the success function and all that. However, I'm calling a function after which iterates through specific elements:
$(".tool-fields.in div.collapse, .common-fields div.collapse").each(...)
Inside this, I'm checking for a specific attribute (custom one using data-) which is also working great; however; the iterator never finishes. No error messages are given, the program doesn't hold up. It just quits.
Here's the function with the iterator
function HideShow() {
$(".tool-fields.in div.collapse, .common-fields div.collapse").each(function () {
if (IsDataYesNoHide(this)) {
$(this).collapse("show");
}
else
$(this).collapse("hide");
});
alert("test");
}
Here's the function called in that, "IsDataYesNoHide":
function IsDataYesNoHide(element) {
var $element = $(element);
var datayesnohide = $element.attr("data-yes-no-hide");
if (datayesnohide !== undefined) {
var array = datayesnohide.split(";");
var returnAnswer = true;
for (var i in array) {
var answer = array[i].split("=")[1];
returnAnswer = returnAnswer && (answer.toLowerCase() === "true");
}
return returnAnswer;
}
else {
return false;
}
}
This is the way the attribute appears
data-yes-no-hide="pKanban_Val=true;pTwoBoxSystem_Val=true;"
EDIT: Per request, here is the jquery $.post
$.post(path + conPath + '/GrabDetails', $.param({ data: dataArr }, true), function (data) {
ToggleLoader(false); //Page load finished so the spinner should stop
if (data !== "") { //if we got anything back of if there wasn't a ghost record
$container.find(".container").first().append(data); //add the content
var $changes = $("#Changes"); //grab the changes
var $details = $("#details"); //grab the current
SplitPage($container, $details, $changes); //Just CSS changes
MoveApproveReject($changes); //Moves buttons to the left of the screen
MarkAsDifferent($changes, $details) //Adds the data- attribute and colors differences
}
else {
$(".Details .modal-content").removeClass("extra-wide"); //Normal page
$(".Details input[type=radio]").each(function () {
CheckOptionalFields(this);
});
}
HideShow(); //Hide or show fields by business logic
});
For a while, I thought the jquery collapse was breaking, but putting the simple alert('test') showed me what was happening. It just was never finishing.
Are there specific lengths of time a callback function can be called from a jquery postback? I'm loading everything in modal views which would indicate "oh maybe jquery is included twice", but I've already had that problem for other things and have made sure that it only ever includes once. As in the include is only once in the entire app and the layout is only applied to the main page.
I'm open to any possibilities.
Thanks!
~Brandon
Found the problem. I had a variable that was sometimes being set as undefined cause it to silently crash. I have no idea why there was no error message.
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.
Rewriting the question -
I am trying to make a page on which if user leave the page (either to other link/website or closing window/tab) I want to show the onbeforeunload handeler saying we have a great offer for you? and if user choose to leave the page it should do the normal propogation but if he choose to stay on the page I need him to redirect it to offer page redirection is important, no compromise. For testing lets redirect to google.com
I made a program as follows -
var stayonthis = true;
var a;
function load() {
window.onbeforeunload = function(e) {
if(stayonthis){
a = setTimeout('window.location.href="http://google.com";',100);
stayonthis = false;
return "Do you really want to leave now?";
}
else {
clearTimeout(a);
}
};
window.onunload = function(e) {
clearTimeout(a);
};
}
window.onload = load;
but the problem is that if he click on the link to yahoo.com and choose to leave the page he is not going to yahoo but to google instead :(
Help Me !! Thanks in Advance
here is the fiddle code
here how you can test because onbeforeunload does not work on iframe well
This solution works in all cases, using back browser button, setting new url in address bar or use links.
What i have found is that triggering onbeforeunload handler doesn't show the dialog attached to onbeforeunload handler.
In this case (when triggering is needed), use a confirm box to show the user message. This workaround is tested in chrome/firefox and IE (7 to 10)
http://jsfiddle.net/W3vUB/4/show
http://jsfiddle.net/W3vUB/4/
EDIT: set DEMO on codepen, apparently jsFiddle doesn't like this snippet(?!)
BTW, using bing.com due to google not allowing no more content being displayed inside iframe.
http://codepen.io/anon/pen/dYKKbZ
var a, b = false,
c = "http://bing.com";
function triggerEvent(el, type) {
if ((el[type] || false) && typeof el[type] == 'function') {
el[type](el);
}
}
$(function () {
$('a:not([href^=#])').on('click', function (e) {
e.preventDefault();
if (confirm("Do you really want to leave now?")) c = this.href;
triggerEvent(window, 'onbeforeunload');
});
});
window.onbeforeunload = function (e) {
if (b) return;
a = setTimeout(function () {
b = true;
window.location.href = c;
c = "http://bing.com";
console.log(c);
}, 500);
return "Do you really want to leave now?";
}
window.onunload = function () {
clearTimeout(a);
}
It's better to Check it local.
Check out the comments and try this: LIVE DEMO
var linkClick=false;
document.onclick = function(e)
{
linkClick = true;
var elemntTagName = e.target.tagName;
if(elemntTagName=='A')
{
e.target.getAttribute("href");
if(!confirm('Are your sure you want to leave?'))
{
window.location.href = "http://google.com";
console.log("http://google.com");
}
else
{
window.location.href = e.target.getAttribute("href");
console.log(e.target.getAttribute("href"));
}
return false;
}
}
function OnBeforeUnLoad ()
{
return "Are you sure?";
linkClick=false;
window.location.href = "http://google.com";
console.log("http://google.com");
}
And change your html code to this:
<body onbeforeunload="if(linkClick == false) {return OnBeforeUnLoad()}">
try it
</body>
After playing a while with this problem I did the following. It seems to work but it's not very reliable. The biggest issue is that the timed out function needs to bridge a large enough timespan for the browser to make a connection to the url in the link's href attribute.
jsfiddle to demonstrate. I used bing.com instead of google.com because of X-Frame-Options: SAMEORIGIN
var F = function(){}; // empty function
var offerUrl = 'http://bing.com';
var url;
var handler = function(e) {
timeout = setTimeout(function () {
console.log('location.assign');
location.assign(offerUrl);
/*
* This value makes or breaks it.
* You need enough time so the browser can make the connection to
* the clicked links href else it will still redirect to the offer url.
*/
}, 1400);
// important!
window.onbeforeunload = F;
console.info('handler');
return 'Do you wan\'t to leave now?';
};
window.onbeforeunload = handler;
Try the following, (adds a global function that checks the state all the time though).
var redirected=false;
$(window).bind('beforeunload', function(e){
if(redirected)
return;
var orgLoc=window.location.href;
$(window).bind('focus.unloadev',function(e){
if(redirected==true)
return;
$(window).unbind('focus.unloadev');
window.setTimeout(function(){
if(window.location.href!=orgLoc)
return;
console.log('redirect...');
window.location.replace('http://google.com');
},6000);
redirected=true;
});
console.log('before2');
return "okdoky2";
});
$(window).unload(function(e){console.log('unloading...');redirected=true;});
<script>
function endSession() {
// Browser or Broswer tab is closed
// Write code here
alert('Browser or Broswer tab closed');
}
</script>
<body onpagehide="endSession();">
I think you're confused about the progress of events, on before unload the page is still interacting, the return method is like a shortcut for return "confirm()", the return of the confirm however cannot be handled at all, so you can not really investigate the response of the user and decide upon it which way to go, the response is going to be immediately carried out as "yes" leave page, or "no" don't leave page...
Notice that you have already changed the source of the url to Google before you prompt user, this action, cannot be undone... unless maybe, you can setimeout to something like 5 seconds (but then if the user isn't quick enough it won't pick up his answer)
Edit: I've just made it a 5000 time lapse and it always goes to Yahoo! Never picks up the google change at all.
hello im trying to make something like github treeslider
im new to javascript..
but heres what im working on
jQuery(document).ready(function(){
$('#red-side-menu a').pjax({
container: '#ajax-users-v1',
});
var toggle;
if (typeof toggle != 'undefined') {
toggle = true;
}
if (toggle) {
$('body')
.bind('start.pjax', function() { $('#ajax-users-v1').show("slide", { direction: "right" }); })
.bind('end.pjax', function() { })
toggle = false;
};
if (!toggle) {
$('body')
.bind('start.pjax', function() { $('#ajax-users-v1').show("slide", { direction: "left" }); })
.bind('end.pjax', function() { })
toggle = true;
}
$('#red-edit-full a').pjax({
container: '#ajax-users-v1',
});
});
well before above im useing php to get $_GET['infolder'] but it seems its not that good.
the problem now that it keeps slide to left
is there a way to do this?
I think this can be simplified.
# this variable maintains state for the lifetime of the page
var direction = "right";
jQuery(document).ready(function(){
# this whole statement only executes once
$('#red-side-menu a').pjax({
container: '#ajax-users-v1'
});
# this line executes once
$('body')
# this line executes once
.bind('start.pjax', function() {
# this line executes every time the start.pjax event reaches the body element
$('#ajax-users-v1').show("slide", { direction: direction });
})
# this line executes once
.bind('end.pjax', function() {
# this line executes every time the end.pjax event reaches the body element (hint: this event is raised after start.pjax is finished)
direction = (direction == "right" ? "left" : "right");
});
# this whole statement only executes once
$('#red-edit-full a').pjax({
container: '#ajax-users-v1'
});
});
The document ready event automatically runs only once. I have commented the code to show when each line or statement block is executed. It's really important to understand that the code inside the event handlers is the only code that is going to run after the page is finished loading.
Simply give a value to x outside the function
var x = true;
jQuery(document).ready(function(){ ...
What is happening here is that you declare var x without giving it a value. It is thus undefined, so typeof x != 'undefined' is false, so you don't end up setting x to true.
(What does x denote, by the way? Please name your variables something a human can understand...)
Then, since undefined is "falsy", the code inside if (!x) gets executed. $('body') gets bound those events, and x gets set to true.
Then the function you passed to jQuery(document).ready ends, and x goes out of scope, never to be seen again or used by anyone. So its existence was pretty pointless; you could have commented out all code except for that before var x, inside if (!x), and $('#red-edit-full a').pjax...
I have the following (javascript/jquery) code to show a busy indicator (after a delay) while an image is loading:
function imgUpdate(arg) {
var loaded = false;
$("#image").one("load", function(){
loaded = true;
$("#busyIndicator").hide();
});
setTimeout(function(){
if (!loaded) {
$("#busyIndicator").show();
}
}, 250);
$("#image")[0].src = arg;
}
Sometimes, the indicator comes up and stays up. How is this possible if the browser's javascript engine is single-threaded? (This is on Firefox 3, by the way.)
One note: this seems to happen when the image being loaded is already cached.
Another note: if I log to my firebug console, all of the lines in imgUpdate are executed, but a log message inside the onload handler never prints on subsequent calls to imgUpdate.
Is there any other javascript on the page that breaks? If so, this may not be a race condition -- JS could simply stop executing before the busyIndicator is hidden again...
I'm hard pressed to replicate this.
Here is the implementation of what you're doing:
A version using caching:
http://jsbin.com/uwuho
A version with caching being prevented: (uses parameter to avoid caching)
http://jsbin.com/oguvi
Hit F5/Ctrl-F5 to see it go. (in particular with the version which prevents caching)
With or without caching neither version is doing what you'd described.
Your problem probably lies elsewhere.
Clearing the image's src tag seems to fix the problem:
function imgUpdate(arg) {
var loaded = false;
$("#image").one("load", function(){
loaded = true;
$("#busyIndicator").hide();
});
setTimeout(function(){
if (!loaded) {
$("#busyIndicator").show();
}
}, 250);
$("#image")[0].src = "";
$("#image")[0].src = arg;
}
You might want to clear the timeout in your callback so that it won't fire if the image is loaded.
var timer = null;
function imgUpdate(arg) {
var loaded = false;
timer = setTimeout(function(){
$("#busyIndicator").show();
timer = null;
}, 250);
$("#image").one("load", function(){
if (timer) {
clearTimeout(timer);
timer = null;
}
$("#busyIndicator").hide();
});
$("#image")[0].src = arg;
}