Develop Reference

jquery unable to show and hide an element

I have div element as
<div class="preview-image hide"><img src="{{STATIC_URL}}ui-anim_basic_16x16.gif"></div>
The hide class belongs to Twitter Bootstrap 2.3.2, the preview-image basically adds some styling to the element and used as handle for JavaScript.
I have jQuery code as below where
$loading.show() and $loading.hide() are not working.
The surprising this is when I run $preview.parent().find('.preview-image').show() from console, its working!!
(function($) {
$(document).ready(function() {
var SET_TIME = 6000;
$('[data-preview]').click(function() {
var $this = $(this);
var $preview = $('#' + $this.data('presponse'));
var $loading = $preview.parent().find('.preview-image');
$loading.show();
$.ajax({
});
$loading.hide();
});
});
})(window.jQuery);

Because $.ajax() is an asynchronous call, the $loading.hide() is being called (as it appears to the user) immediately after the $loading.show(). In order to circumvent this, you should make the $loading.hide() call after your AJAX call is complete. One way to do this is:
var $loading = $preview.parent().find('.preview-image');
$loading.show();
$.ajax({
}).always(function() {
$loading.hide();
});

Is the issue that it's hiding straight away? I think the hide needs to be within a success function of the AJAX call rather than being after it.
Eg.
$.ajax({
success: function() {
$loading.hide();
}
});

Hide loading gif after ajax callback

I have a simple question but I couldn't find a clean answer. I need to load heavy images after an ajax call and I want to use an animated gif as a pre-loader. I'm using the follow code:
function loadProducts(url) {
$("#loading").show();
$('#inner').fadeOut(1).load(url + ' .product-list', function() {
$('#inner').fadeIn(1000, function() {
$("#loading").hide();
});
});
}
The #loading is hiding when the HTML is loaded .load(url + ' .product-list'. The problem is that the heavy images are still rendering on the screen and I would like to keep showing the animated .gif until the renders of the images are finished. Is there a way to know when the images on the screen are rendered?.
Thanks in advance.

You can use promises to check when all the images have loaded, and then remove the loading gif.
This creates a promise that is resolved when the image has loaded, all the promises are kept in an array, and when all promises are resolved, i.e. all images are loaded, the callback fires.
function loadProducts(url) {
$("#loading").show();
$('#inner').fadeOut(1).load(url + ' .product-list', function() {
var promises = [];
$('#inner').find('img').each(function(_, image) {
var img = new Image(),
def = new $.Deferred();
img.onload = function() {
def.resolve();
}
promises.push( def.promise() );
img.src = image.src;
if (img.complete) img.onload();
});
$.when.apply(undefined, promises).done(function() {
$('#inner').fadeIn(1000, function() {
$("#loading").hide();
});
});
});
}

You can use ImagesLoaded
Sample usage
imagesLoaded( document.querySelector('#container'), function( instance ) {
console.log('all images are loaded');
});
// selector string
imagesLoaded( '#container', function() {...});
// multiple elements
var posts = document.querySelectorAll('.post');
imagesLoaded( posts, function() {...});

Could add/remove the loader as a class? I have base 64encoded the loader, so there is no pre loader required. This also uses a closure to allow the counter to remember its value.
var imgDiv = document.getElementById("imgDiv");
imgDiv.onclick = (function () {
"use strict";
var count = 0; // init the count to 0
return function () {
count++; //count
if (count === 1) { // do something on first click
$('.img-loader-content').addClass('loader');
$('.imgDiv').load("images/img.jpg", function () {
$('.img-loader-content').removeClass('loader');
});
}
if (count > 1) {
$('.imgDiv').slideToggle(400);
}
};
})
();

You may try using Image object. E.g:
function loadImage(url) {
$("#loading").show();
var img = new Image();
img.src = url;
img.onload = function(e) {
$("#loading").hide();
//ur code to append/show the image
};
}

the most approach to this is using onLoad , so basically after the success call of ajax , invoke another call into success function :
http://www.w3schools.com/jsref/event_onload.asp
onload is most often used within the element to execute a
script once a web page has completely loaded all content (including
images, script files, CSS files, etc.).
or use native solution like this :
<img src="w3javascript.gif" onload="loadImage()">
http://www.w3schools.com/jsref/event_img_onload.asp
Also last answer of this question is very useful in your case :
Is there something similar to `$(window).load();` for executing a function after newly inserted Ajax content has finished loading?

You can do it easily by ajaxComplete callback, here check an example http://www.w3schools.com/jquery/tryit.asp?filename=tryjquery_ajax_ajaxcomplete

Loading GIF while AJAX completes

This should be quite simple but I'll be darned if I can work it out. Just trying to get a div to display while my ajax is processing and then hide once done (I've put a sleep in there purely to test its working as locally it loads so fast I'm not sure if its working or not)!
The html page has this code in the script: -
$(document).ready(function(){
$("#loadingGIF").ajaxStart(function () {
$(this).show();
});
$("#loadingGIF").ajaxStop(function () {
window.setTimeout(partB,5000)
$(this).hide();
});
function partB(){
//just because
}
var scenarioID = ${testScenarioInstance.id}
var myData = ${results as JSON}
populateFormData(myData, scenarioID);
});
There is then a div in my page like so (which I can see in the source of the page just hidden): -
<div id="loadingGIF" ><img src='${application.contextPath}/images/spinner.gif' height="50" width="50"></div>
The ready code then goes off and calls this: -
function populateFormData(results, scenarioID) {
$table = $('#formList')
for(var i in results){
var formIDX = (results[i]["forms_idx"])
var formID = (results[i]["form_id"])
appendSubTable(formIDX, scenarioID, $table, formID);
}
}
Which references this multiple times calling several AJAX posts: -
function appendSubTable(formIDX, scenarioID, $table, formID) {
var $subTable = $table.find("#" + formIDX).find('td:eq(1)').find("div").find("table")
var url = "**Trust me this bits OK ;) **"
$.post(url, {
formIDX : formIDX, scenarioID : scenarioID, formID :formID
}, function(data) {
$subTable.append(data)
}).fail(function() {
});
}
Any pointers gratefully received...
Interestingly I bunged some alerts into my ajaxstart and stop and neither show up ever so I'm missing something obvious :S When I check the console in firefox I can see that all my POSTs are completing....

You should probably add the Ajaxstart and stop global event handlers to the document node like this
$(document).ajaxStart(function () {
$("#loadingGIF").show();
});

I realized my problem, I needed to register the ajaxstart and stop to the document not the div!
So instead of this: -
$("#loadingGIF").ajaxStart(function () {
$(this).show();
});
I now have: -
$(document).ajaxStart(function () {
$("#loadingGIF").show();
});
I assume this is because its the document that the ajax is running against not the div although my understanding there may not be 100% accurate at least this works so please tell me if I've misunderstood this! :)
#jbl, thanks for this pointer I did this to also leave the notification on screen for a few more moments just to make sure everything is loaded.

How To Call Function on page Loading

I'm Using Web service using AJAX Call In My HTML Page . Web Service Returning Data Nearly 30 to 40 second's .
During This Loading Time I Need to Use Some Loading Gif Images After Data Completely Received Form Web Service The Loading Image Must Be Hide.
I'm Using Only HTML,JAVASCRIPT,CSS,J Query.
Any Idea Or Samples Needed.
I'm Using Following Code
$(document).ready(function () {
document.write('<img src="http://www.esta.org.uk/spinner.gif">');
});
$( window ).load(function() {
//This following Function Related To My Design
jQuery(".chosen").data("placeholder", "Select Frameworks...").chosen();
var config = {
'.chosen-select': {},
'.chosen-select-deselect': { allow_single_deselect: true },
'.chosen-select-no-single': { disable_search_threshold: 10 },
'.chosen-select-no-results': { no_results_text: 'Oops, nothing found!' },
'.chosen-select-width': { width: "95%" }
}
for (var selector in config) {
$(selector).chosen(config[selector]);
}
});
In The Above Code My Problem Is On Page Load Gif Image Show But It's Not Hide Only Gif Image Only Showing.

Put a hidden image on your page and as soon as your ajax call is made, make that image visible
$('#image').show();
$.ajax({
complete: function(){
$('#image').hide();
}
});
and hide that image again on Complete of Ajax call.

Use your ajax request callback (on success/failure) instead of page load.

When sending the request just show a gif animation by setting the Display to block
then when you have the data set the display to none
or use jquery
function showHourGlass()
{
$("#gifimage").show();
}
function hideHourGlass()
{
$("#gifimage").hide();
}

You ask for ideas, I have one sample -
http://www.myntra.com/shoes
load scroll down fastly this is the ajax jquery request which is exact output which you have mentioned in your question
Check source code
Jquery Ajax loading image while getting the data
This what the html looks like:
<button id="save">Load User</button>
<div id="loading"></div>
and the javascript:
$('#save').click(function () {
// add loading image to div
$('#loading').html('<img src="http://preloaders.net/preloaders/287/Filling%20broken%20ring.gif"> loading...');
// run ajax request
$.ajax({
type: "GET",
dataType: "json",
url: "https://api.github.com/users/jveldboom",
success: function (d) {
// replace div's content with returned data
// $('#loading').html('<img src="'+d.avatar_url+'"><br>'+d.login);
// setTimeout added to show loading
setTimeout(function () {
$('#loading').html('<img src="' + d.avatar_url + '"><br>' + d.login);
}, 2000);
}
});
});
I hope this will help you.

when is triggered AJAX success?

I want load some HTML document by AJAX, but I want to show it when all images in this document are loded.
$('.about').click(function () {
$(".back").load('Tour.html', function () {
$(".back").show();
});
});
".back" should be visible when all images in Tour.html are loaded, when is triggered a success event??

$(".back").load('Tour.html', function (html) {
var $imgs = $(html).find('img');
var len = $imgs.length, loaded = 0;
$imgs.one('load', function() {
loaded++;
if (loaded == len) {
$(".back").show();
}
})
.each(function () { if (this.complete) { $(this).trigger('load'); });
});
This requires at least one <img> in the returned html.

What I would suggest is to use an iframe instead. Here is some sample code in plain JavaScript:
var ifr=document.createElement("iframe");
ifr.style.display="none";
document.body.appendChild(ifr);
ifr.onload=function() {
// Do what you want with Tour.html loaded in the iframe
};
ifr.src="Tour.html";

ImagesLoaded is what you are looking for.
Place all code (ajax request in this case), when the images specified are loaded.
The plugin specifies why you cannot use load() on cached images