The role of the script is to change image.jpg with newimage.gif and vice versa when clicked.
Now i want to add a spinner while the newimage.gif loads.
Something like on 9gag.com/gif .
Can someone help me please?
This is the code:
html
<img src="/image.jpg" id="pic" onclick="change()"/>
<a id="first" href="/newimage.gif" style="display:none;"></a>
<a id="second" href="/image.jpg" style="display:none;"></a>
javascript
function change(){
var imag = document.getElementById('pic').src;
var img = imag.slice(-3);
var img1 = document.getElementById('second').href;
var imag2 = document.getElementById('first').href;
if(img == 'gif') {
document.getElementById('pic').src=imag2;
// here the newimage.gif changes to image.jpg
} else {
// here the image.jpg changes to newimage.gif
// i think here should be the code that will display a spinner while the image.gif loads completely
document.getElementById('pic').src=img1;
}
}
The easiest way might be to set the CSS background-image property of the images to a loading spinner graphic.
HTML:
<img src="path/to/real/image.jpg" class="loading">
CSS:
img.loading {
background: transparent url(path/to/loading.gif) no-repeat scroll center center;
}
Once the actual image is downloaded, it covers up the "loading" animated GIF background image.
If you have GIFs or JPGs saved with Progressive display, you'll want to resave those images without that option so the real image is invisible until the full image is downloaded allowing your spinner graphic to show through in the meantime.
Have a look at this: http://www.appelsiini.net/projects/lazyload.
Images outside of viewport are not loaded until user scrolls to them, and you have the aboility to have a small image placeholder untill it's loaded...
I've actually used it here, on a testing site, some time ago: http://dev.thomaskile.me/?page=test-zone&module=Masonry.
I found a kind of way, the only problem is that after the image.gif gets loaded the spinner still appears.
if(img == 'gif') {
document.getElementById('pic').src=imag2;
// here the newimage.gif changes back to image.jpg
document.getElementById("spinner").style.display = "none";
} else {
document.getElementById('pic').src=img1;
var image = new Image();
image.src = document.getElementById('second').href;
var x = image.complete;
if(x) {
document.getElementById("spinner").style.display = "none";
} else {
document.getElementById("spinner").style.display = "block";
}
}
}
This is here i use the script http://www.2lol.ro/load/poze_haioase_miscatoare/20?ref=stk
Have you checked out this site for a configurable spinner without additional graphics that can be attached to any dom element ? starting / stopping the spinner boils down to 2 js function calls.
the code comes under the mit license, the minified js standalone file takes 9kb, glue code for use as a jquery plugin is provided and there is a vml fallback for, err... steampunk browsers ;-).
i'm not affiliated in any way with code or author.
Related
UPDATE:
I just found some more info. It seems that in Chrome, the currentSrc of the image will often be empty, whereas in Firefox, the URL is always correct. Is the JS trying to access currentSrc before it's available? Is there a way to prevent this?
I am creating a Drupal 8 website, and in order to use the responsive images module with a background-image, I came up with the following workaround. The JS function below, setParallaxImage(), takes the currentSrc from the img in the picture element and sets it as the background-image for the outermost div. The img itself is not displayed (display: none in CSS) and is given a dummy image, as I only need it to get the currentSrc. The function is called with onload and onresize.
The code seems to work well in Firefox. When resizing the browser past a breakpoint, the image goes grey for a split second, then loads the image from the proper source. However, with Chrome, when quickly resizing past a breakpoint, the image may become grey and not get displayed at all, that is, background-image: url(). Usually if I resize the window a couple more times, the image will finally appear. Does anyone know why this might be happening? Thank you for reading.
JS
function setParallaxImage() {
const parallaxContainer = document.getElementsByClassName('paragraph--type--parallax-banner-with-text');
for(var i = 0; i < parallaxContainer.length; i++) {
console.log('in setparallax');
var x = parallaxContainer[i];
var parallax = x.getElementsByClassName('field--name-field-parallax-image-top-')[0];
var picture = parallax.getElementsByTagName("picture")[0];
var sourceURL = picture.querySelector('img').currentSrc;
x.setAttribute('style', 'background-image: url(' + sourceURL +')');
var img = picture.getElementsByTagName("img")[0].setAttribute('src', '/sites/default/files/src_images/dummy_image.gif');
}
}
window.onload = setParallaxImage
window.onresize = setParallaxImage;
HTML
<div class='paragraph--type--parallax-banner-with-text'>
<div class='field--name-field-parallax-image-top-'>
<picture>
<!-- several source tags here -->
<img src="will-be-given-dummy-image-in-JS">
</picture>
</div>
</div>
You can use the property "complete" to check, if the image was already loaded. If not, u can use the onload-Event to fire, when the image is available.
if (img.complete) {
console.log(img.currentSrc);
} else {
img.onload = function() {
console.log(img.currentSrc);
}
}
I am trying to find a more modern solution that doesn't use jQuery as I am using React (Gatsbyjs specifically).
I have a website with multiple image carousels that contain high res images.
The issue is the each image carousel only show one image at a time, so only when the user navigates to the next image does the image get fetched, this results in a choppy loading appearance.
I have tried researching online with onLoad and load event listeners but none seem to have worked so far because they only load the image that is currently being shown by the carousel, instead of all of the images in the carousel.
If there is a way to first load all the images, then set the state to true, and only after the state is true, then the rest of the DOM appears onto the screen, that would be perfect.
Any suggestions? Thanks.
Website in question: https://dev--yachtgamechanger.netlify.com/
As Lonnie Best said, I ended up using Promise.all() to capture the loads of the images.
Just in case anyone else want to check it out:
https://codesandbox.io/s/react-image-preload-ptosn
I guess that your lib is using lazy load approach. And it's really good when dueling with high res images.
You still can change the approach to load all the images before rendering the UI, by going into the carousel component, change the rendering behavior by checking whether all images be loaded or not before render.
Updated: Because you are using gatsby-image, so just use this property:
loading: "eager". For EX:
<Img
fixed={data.file.childImageSharp.fixed}
alt="Gatsby Docs are awesome"
loading="eager"
/>
https://www.gatsbyjs.org/packages/gatsby-image/
You can ensure that an image is pre-downloaded 100% well before it gets displayed to the screen.
Simply create an Image element and set its src property to the URL where the image is located. Then use the image's onload event to detect when it is ready for instant display.
// Image to Pre-Download:
var image = new Image();
console.time("Image Fully Downloaded in");
image.src = "https://www.nasa.gov/sites/default/files/thumbnails/image/pia24870.jpeg";
image.onload = function()
{
console.timeEnd("Image Fully Downloaded in");
console.log("Image is ready for viewing.");
clearInterval(interval);
progress.parentNode.replaceChild(btn, progress);
}
// Fake Progress Indicator:
let progress = document.createElement("progress");
progress.value = 3;
progress.max = 100;
progress.textContent = "Fake Progress";
document.body.appendChild(progress);
let interval = setInterval(()=>
{
if (progress.value === 99)
{
progress.value = 0;
}
else
{
progress.value = progress.value + 1;
}
},50)
// Button to Replace Progress Indicator:
let btn = document.createElement("button");
btn.textContent = "View Entire Image Instantly";
btn.addEventListener('click',function()
{
this.parentNode.replaceChild(image, this);
});
img { max-width: 100%; }
<p>Only after the image is completely downloaded, will you see the button to view it:</p>
Based on this concept, you could pre-load/queue as many images as you like into image objects, so that they are ready to be displayed instantly (well before the user decides to view the next image). Here's an example where I'm switching between preloaded images automatically (so fast that it looks like an animated gif -- but it is actually 27 separate images from 27 different URL locations): See statue example and view source.
I'd like to make GIF's only starting to play once they are actually on the screen. I came up with a small JS Script that basically replaces a static image (the first frame of the gif) with the actual gif, as soon as the image is on the monitor.
I can't really change that much in the HTML section since i'm working in a CMS.
HTML:
<div class="lazy">
<img src="firstframe.png">
<img src="gif.gif">
</div>
JS:
var lazies = $('.lazy');
lazies.each(function(){
var src = $(this).find('img').eq(1).attr('src');
if($(this)[0].offsetTop <= window.innerHeight && !$(this).hasClass('lazyactive')){
$(this).find('img').eq(0).attr('src', src);
$(this).find('img').eq(1).hide();
$(this).addClass('lazyactive');
}
})
window.onscroll = function(){
lazies.each(function(i){
if(window.pageYOffset + window.innerHeight >= $(this)[0].offsetTop && !$(this).hasClass('lazyactive')){
var src = $(this).find('img').eq(1).attr('src')
$(this).addClass('lazyactive');
$(this).find('img').eq(0).attr('src', src);
$(this).find('img').eq(1).hide();
}
})
}
The code works fine as long as i have different GIF's on the page.
But as soon as i have the same GIF multiple times on the page, i have a problem. Every time one of the PNG get's replaced with the GIF (by scrolling down), every GIF starts to play from beginning.
I'm not sure if that's normal behaviour of the browsers or the error is in my script..
I have a large gif animation on a web page and want to start it not until it's completely finished loading. How would that be possible using JavaScript / jQuery?
Use a placeholder image, and replace it with the animated GIF once that GIF is fully loaded:
<img id="anim" src="placeholder.gif">
JS:
var myanim = new Image();
myanim.src = '/img/actions.png';
myanim.onload = function() {
document.getElementById('anim').src = myanim.src;
}
http://jsfiddle.net/mblase75/6XTg7/
You can hide GIFs with CSS (or JS replacing them with a placeholder) and when GIFs are loaded you can fire show()
$('img[src$=".gif"]').load(function(){$(this).show())
You could hide it until it is fully loaded.
<!--- this uses jquery !-->
<script type="text/javascript">
var image_url = "http://media.tumblr.com/tumblr_m4doax3R071r9c1z7.gif";
var image = $('<img />').load(function(){
$(this).show();
}).attr('src', image_url).hide();
$('body').append(image);
</script>
The issue here is that once the image has been downloaded (i.e it is in the browsers cache), there really doesn't seem to be any way of starting it from a particular frame.
You have no control over gif animation through javascript, so you have to implement some sort of a hack. You have to make it hidden in the beginning. Instead of the actual picture you can put a div with the dimensions of the actual picture and with text like "wait".
When the image is downloaded in the browser you can substitute div with an image. And at that point of time animation will start
I have a problem with a mouseover script. Everything works as it should but I have a small issue that I don't know how to solve. More precisely, the mouseover script creates a grayscale image hover effect. When the page loads the colored images are showing for a short time (1 second or less) and then the javascript is applied and they are all grayed out which is exactly how things should work.
How can I make it so that the colored images will not appear before the javascript is applied? Basically, I want the grayscale images to appear when the page loads not after. Is it possible?
You can see the script here and the webpage in question here.
I would remove the images from the HTML and load them dynamically.
I would use <a class="placeholder" href=""></a> as placeholders for the <img src="" /> and would style the links to either be hidden or go well with the design.
$('a.placeholder').each(function() {
var src = $(this).attr('href');
var image = new Image(); // this is not yet visible in the DOM.
image.onload = grayscale; // change the grayscale function to accept
// event parameters
image.src = src; // this triggers the onload event which
// grayscales the image
var dom_image = $('<img />').attr('src', src);
$(this).replaceWith(dom_image);
});
Of course you have to be doing the above on document ready not on window load.