Problem with degradable JavaScript slideshow - javascript

UPDATE: I've edited the code below to show what I was using when I tried to work with CSS visibility. I'm still stuck with this problem. I've also tried to remove the preloader() function from the body onLoad, but I can't use getElementById because the element hasn't loaded. My final thought was to just call rand(5) from within the HTML itself so that it adds a number to the end of the image filename if Javascript is enabled, but I'm not even sure how to incorporate that directly into the HTML. Any help would be greatly appreciated!
I created a slideshow with Javascript. The HTML calls a static image to display in the event Javascript is not enabled in the browser. If Javascript is enabled in the browser, it is supposed to load a random image in the place of the static image.
The problem I'm encountering is when Javascript is enabled, you see the static image load with the page and then, if the random image is different, you see it quickly load right after that. So it looks like two images cycling quickly on page load.
Here is the Javascript code I'm using:
// Define images used in slideshow
imgArray = new Array(
"header_img1.jpg",
"header_img2.jpg",
"header_img3.jpg",
"header_img4.jpg",
"header_img5.jpg"
);
baseURL = "images/";
// Preload slideshow images
function preloader() {
domElement = document.getElementById('gallery-image');
domElement.style.visibility = "hidden";
// counter
var i = 0;
// create object
imageObj = new Image();
// start preloading imgArray
for (i=0; i<3; i++) {
imageObj.src=imgArray[i];
}
}
// Select random image to display for slideshow
function random_img() {
domElement.style.visibility = "visible";
rand = Math.round(Math.random()*(imgArray.length - 1));
document["faces"].src = baseURL + imgArray[rand];
rand += 1;
}
Here is the accompanying HTML:
<body onLoad="preloader();random_img();">
.
.
.
<a href="#" onclick="f_slideshow(-1);return false;">
<img src="images/header_img1.png" alt="" width="26" height="207" /></a>
<img src="images/header_img1.jpg" alt="" width="529" height="197" class="img-1" name="faces" />
<a href="#" onclick="f_slideshow(1);return false;">
<img src="images/header_img2.png" alt="" width="27" height="207" /></a>
How do I change what I have so when Javascript is enabled, you don't see the two cycling images?

In your preLoader() manipulate the style to hide the elements you wish to hide if javascript is enabled.
This way, if it is enabled the elements will hide, if it is not, the clearly the javascript to hide them will not run.
example
var domElement = document.getElementById('id-of-element');
domElement.style.display = 'none';

This is the JavaScript code that solved my problem:
// Define images used in slideshow
imgArray = new Array(
"header_img1.jpg",
"header_img2.jpg",
"header_img3.jpg",
"header_img4.jpg",
"header_img5.jpg"
);
baseURL = "images/";
// Hide static image and preload slideshow images
function preloader() {
// counter
var i = 0;
// create object
imageObj = new Image();
// start preloading imgArray
for (i=0; i<3; i++) {
imageObj.src=imgArray[i];
}
}
// Control previous/next functions of slideshow
numImages = imgArray.length;
function f_slideshow( xflip ) {
// grab source of current image
var curImage = document["faces"].src;
// get image number from string and convert to int
curImage = parseInt(curImage.substring(curImage.length-5, curImage.length));
// create source for next/previous link
curImage = curImage + xflip;
if (curImage > numImages)
{ curImage = 1 ; }
if (curImage == 0)
{ curImage = numImages ; }
document["faces"].src = baseURL + imgArray[curImage - 1];
}

Related

Image Loading detecting using Javascript

I have a lot of images (of 5 categories) in my website which make it load slowly.
I set every image with Attribute "data-src" containing its real source, and I update its source attribute with this "data-src" attribute for every image in this categroy (inside a for loop), whenever the relevant category is chosen (clicked).
HTML:
<img loading="lzay" class="post_image" data-src="https://i.ibb.co/FswR5KB/Pics-Art-06-22-07-48-49.jpg" src="https://i.ibb.co/FswR5KB/Pics-Art-06-22-07-48-49.jpg">
JAVASCRIPT:
for(i = 0; i< selection.length; i++){
let data_src = selection[i].children[2].getAttribute("data-src");;
selection[i].children[2].src = data_src;
}
How can I tell when all of the images of a category was loaded to the site?
(some code continue to run after the for loop is done, yet not all the images loaded and I wish the rest of the code will fire only after they are loaded to page).
Try this. I didn't have much time to come up with it, but it might work. Sorry if it doesn't.
index.html
<img id="img1" src="https://i.ibb.co/FswR5KB/Pics-Art-06-22-07-48-49.jpg"/>
<img id="img2" src="https://i.ibb.co/FswR5KB/Pics-Art-06-22-07-48-49.jpg"/>
<img id="img3" src="https://i.ibb.co/FswR5KB/Pics-Art-06-22-07-48-49.jpg"/>
<script type="text/javascript" src="script.js"></script>
script.js
const img1 = document.getElementById("img1");
const img2 = document.getElementById("img2");
const img3 = document.getElementById("img3");
const imgArray = [
img1,
img2,
img3
]
let imgsLoaded = 0;
for (let i = 0; i < imgArray.length; i++) {
imgArray[i].onload = function () {
imgsLoaded++;
}
if (imgsLoaded >= imgArray.length) {
// all images are loaded
}
}

How to display an array of images as a list and make them clickable to display some text using javascript?

I need to display a list of images from an array and also make it clickable to display some text on click. Looking for some simple solution only with javascript.
var images = ["img1", "img2", "img3"];
var allPics = images.length;
var i = 0;
for(;i<allPics; i++){
myImg.src = images[i];
}
Example here:
https://jsfiddle.net/gmqLtd1u/1/
Now only one image is displayed.
Now only one image is displayed.
Because you're using one <img> and update its src several times in loop. After last iteration, its src is not updated anymore. That's why you see the last image.
Change your html, so that instead of <img> you have <div> as container/placeholder:
<!-- <img id="myImg"/> -->
<div id="myImg"></div>
And change your JS, to create <img> and append it to <div>:
for(;i<allPics; i++){
// myImg.src = images[i];
// TODO: adjust this to whatever you want
// in this example, use `<a>` that link to another page
// you can use javascript to show modal/alert too
var a = document.createElement('a');
a.href = 'example.html'; // TODO: adjust this
var img = document.createElement('img');
img.src = images[i];
a.appendChild(img);
document.getElementById('myImg').appendChild(a);
}
And maybe your CSS, to match with new output:
#myImg img {
...
}

display series of images on button click

is it possible to display 3 images one after another at each button click using a array in JavaScript?
I have an array called
var images = ["image1.jpg","image2.jpg","image3.jpg"]
The way I need the website to load is for the first picture to already be there. Then when I click on the button I want the next picture to be displayed however replacing the image that was there before. I want this to repeat throughout the entire, so when I click on the button, and if the image being displayed was image3, then image1 should be displayed.
I want to share the code I have so far however I don't know where to start. the only code i have is the layout and a variable.
var images = ["image1.jpg","image2.jpg","image3.jpg"]
Try like this.Use 'document.querySelector' do select your button.On clicking button appen images using forEach in body.
var button = document.querySelector('#show');//selects your button
button.addEventListener('click',function(){ // handle click event
var images = ["image1.jpg","image2.jpg","image3.jpg"];//array of valid images
images.forEach(function(image){
img = document.createElement('img');//creates a img element
img.src = image;//sets src of img tag
document.body.appendChild(img)//appends into body
});
});
<button id="show">
Show images
</button>
Pure JS solution.
var images = ["http://placehold.it/350x150", "http://placehold.it/250x150", "http://placehold.it/150x150"];
var elem = document.getElementById('img');
var i = 0;
window.onload = function() {
elem.setAttribute("src", images[i]);
}
elem.addEventListener('click', function() {
(i < images.length-1) ? i++ : i = 0;
this.setAttribute("src", images[i]);
});
<img src='' id='img'>
jQuery solution.
var images = ["http://placehold.it/350x150", "http://placehold.it/250x150", "http://placehold.it/150x150"];
var i = 0;
$(document).ready(function() {
$('#img').attr('src', images[i]);
});
$('#img').click(function() {
(i < images.length-1) ? i++ : i = 0;
$('#img').attr('src', images[i]);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<img src='' id='img'>

Showing random divs images every time page is load

Lets say I have these images gallery, how do i randomly display the images everytime when i reload the page?
http://creativepreviews.com/fiddle/study/20131007/
Let's say the image will display in the background of the DIV, then the following should do it.
// JS
var imgArray = ["img1.jpg", "cat.jpg", "sky.jpg"]
function randomBg() {
x = Math.random()
y = Math.round(x * 10)
if (imgArray[y] != undefined) {
document.getElementById("blah").style.backgroundImage = "url('" + imgArray[y] + "')"
} else {
document.getElementById("blah").style.backgroundImage = "url('default.jpg')"
}
}
...and the HTML.
<script src="test.js"></script>
<body onload="randomBg()">
<div id="blah"></div>
...or you could replace the style.backgroundImage in the JS with innerHTML = <img src=" etc...
You could do something along these lines (not tested)
var grd = $('#grid');
var imgs = grd.children();
imgs.sort(function(){return (Math.round(Math.random()) - 0.5);});
grd.remove('li');
for(var i=0;i < imgs.length;i++) grd.append(imgs[i]);
In essence what we are doing is getting all the li elements in 'grid' into an array, randomizing them, removing them all from 'grid' and then putting them back in again.
If you had supplied a working fiddle rather than a link to the finished article it would be easier to modify it and provide a more complete solution.

Javascript gallery with prev/next function AND thumbnail... nothing else

Short of going for something like Galleriffic
and modifying, hiding and removing elements, what would be a way to add a function by which thumbnails can also be clicked to display the image?
Much obliged to anyone who can point me in the right direction. I'm using the following by Paul McFedries at mcfedries.com.
<script type="text/javascript">
<!--
// Use the following variable to specify
// the number of images
var NumberOfImages = 3
var img = new Array(NumberOfImages)
// Use the following variables to specify the image names:
img[0] = "yellow1.jpg"
img[1] = "blue2.jpg"
img[2] = "green3.jpg"
var imgNumber = 0
function NextImage()
{
imgNumber++
if (imgNumber == NumberOfImages)
imgNumber = 0
document.images["VCRImage"].src = img[imgNumber]
}
function PreviousImage()
{
imgNumber--
if (imgNumber < 0)
imgNumber = NumberOfImages - 1
document.images["VCRImage"].src = img[imgNumber]
}
</script>
in the html:
<div class="galleryarrows">
<A HREF="javascript:PreviousImage()">
<IMG SRC="previous.png" BORDER=0></A>
<A HREF="javascript:NextImage()">
<IMG SRC="next.png" BORDER=0></A>
</div>
A quick, basic solution: Save the full size versions of your images in a folder called say, 'full_images', with the same names as the thumbnails.
Add an onClick event into the element img elements that display your thumbnails in the html, so they look something like this.
<img src = "yellow1.jpg" name = "thumb[0]" style = "cursor:pointer" onClick = "Javascript:DisplayImage(0);" alt = "yellow"/>
<img src = "blue2.jpg" name = "thumb[1]" style = "cursor:pointer" onClick = "Javascript:DisplayImage(1);" alt = "blue"/>
<img src = "green3.jpg" name = "thumb[2]" style = "cursor:pointer" onClick = "Javascript:DisplayImage(2);" alt = "green"/>
In your javascript, add this function
function DisplayImage(id){
imgNumber = id;
document.images["VCRImage"].src = "full_images/" + img[id];
}
This will display in an element with the name 'VCRImage'.
Not my favourite solution this, but quick, and should work. If Javascript is new to you, then you might as well check out jQuery. It's a lot easier to use, and is way more cross-browser compatible.

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