Preloading images with Prototype/Scriptaculous - javascript

I'm using Prototype/Scriptaculous library for a featured content slider, it works great but the images need to be preloaded.
I've used jQuery mostly so I'm not sure how its done with Prototype. Here's the slider script if you'd like to take a look.

You can do this with a few simple lines of Javascript
var preload = []
for(var x=0;x<slider_images.length;x++) {
preload[x] = new Image()
preload[x].src = slider_images[x]
}

Related

JavaScript Image Preload in function

first of all I don't really know anything about JavaScript.
I have a website slideshow with the following code:
//* Slideshow 1 *//
var slider_img_1 = document.querySelector(".image_slide_1");
var images_1 = ["fabric1_1.jpg", "fabric1_2.jpg", "fabric1_3.jpg", "fabric1_4.jpg", "fabric1_5.jpg"];
var i = 0;
//* Slideshow 2 *//
var slider_img_2 = document.querySelector(".image_slide_2");
var images_2 = ["book1_1.jpg", "book1_2.jpg", "book1_3.jpg", "book1_4.jpg", "book1_5.jpg", "book1_6.jpg", "book1_7.jpg"];
var j = 0;
When clicking on the slideshow the images cycle through.
Is it possible to let the images inside the var brackets preload, because currently they only start loading when clicking on the slideshow, which takes a lot of time in my case.
I hope you understand my question well. Thank you guys!
In this use case (if you need to load images with JavaScript) it would probably be best to append you images in to HTML when page is loaded and hide them, with CSS for example, when they shouldn't be visible.

Displaying image from Javascript to Processing.js canvas

So, I'm trying to programmatically add an image to my canvas, from a Javascript function :
// Spawn function
var spawnWrapper = function() {
myCanvas = Processing.getInstanceById('mycanvas');
// myCanvas.ellipse(50,50,50,50); // works fine here too
myImage = myCanvas.loadImage('pegman.png');
myCanvas.image(myImage,0,0);
};
The same successive calls in console works :
Also, there are no errors mentioned on the console.
I'm really stuck there and would appreciate any help ;-)
I suspect that you might be missing the preload directive.
This directive regulates image preloading, which is required when
using loadImage() or requestImage() in a sketch. Using this directive
will preload all images indicated between quotes, and comma separated
if multiple images are used, so that they will be ready for use when
the sketch begins running.
I hope that helps. I'm curious as to why you're using processing.js instead of P5.js?
Good luck.

jQuery image preload

I got a web application, in which there are some images.
Will show a overlay in my page at start and that will automatically fadeout on all images loades.
I need something like this
its rough code
var image1="image1.jpg";
var image2="image2.jpg";
var image4="image4.jpg";
image1 & image2 & image4 loaded then fadeout #preload and show content.
Please help me ... I tried this .. but not working ..
var img1 = new Image();
img1.src = "../images/wall.jpg";
img1.onload = function() {
alert("loaded");
};
var images_loading = $('img').length;
$('img').load(function(){
if(!--images_loading) {
// all images loaded
}
});
Please mind you can't use display:none to hide images.
Using display:none will block image download by your browser. User visibility:hidden instead.
Try this fiddle. I've made it using mostly raw javascript.
If you want, you could use jQuerys .load to replace the onload function, and append to replace appendChild

Displaying an image using only javascript

I am trying to display an image using purely javascript. I have found various examples that work using html and javascript, but no pure javascript solution. Here is the non working code I have right now,
<script type="text/javascript">
if(document.images)
(new Image()).src="http://www.example.com/image.png";
</script>
var img = new Image();
img.src = "http://www.example.com/image.png";
document.body.appendChild(img); //Make sure you put the element in the DOM, otherwise it won't be visible.

Changing background images, Jquery + CSS

I am working on a clients website and want the background images on the "cruise_offers" div to change, possibly only 3 - 4 images in rotation.
My jquery knowledge is quite basic so any help would be great.
I would prefer it to work with jQuery as I am using it elsewhere on the site.
My markup:
<div class="cruise_offers">
<span class="overlay_bar">
View our Great Cruise Offers
</span>
</div>
Cheers
Rory
Check out this link - I worked on something similar and it may help:
I found a jquery image rotatation script and adding hyperlinks to the images breaks the animation
$(div.cruise_offers).removeClass('cruise_offers');
$(div.cruise_offers).addClass('cruise_offers1');
create classes in your css with different background images.
Maybe something like this would work (I haven't tested it).
var current_image = 0;
var rotation_speed = 5000; //milliseconds
var where = $("div.cruise_offers");
var images = new Array();
images[0] = 'img1.jpg';
images[1] = 'img2.jpg';
function change_image() {
current_image++;
if (images[current_image].length == 0) {
current_image = 0;
}
$(where).css("background-image", "url("+images[current_image]+")")
}
if (where.length != 0) {
setTimeout("change_image()", rotation_speed);
}
Check out the Cycle plugin and visit the demos at the bottom of the page to get started.

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