i'm trying to cycle through 3 images using a for loop in javascript. Here is my code:
<img name="slide" width="300" height="300">
var i=0;
var images = [];
images[0] = "images/1.jpg";
images[1] = "images/2.jpg";
images[2] = "images/3.jpg";
function changeImage () {
for(i=0; i < images.length; i++) {
document.slide.src = images[i];
}
}
window.onload = changeImage;
Currently, only image 3 is displayed. Anyone know what i'm doing wrong here?
Yes - this is because your for loop run finishes instantly so there's no time for slides 1 and 2 to be shown.
Give this a try:
var currentImage = 0,
images = [
"https://unsplash.it/200/300?image=100",
"https://unsplash.it/200/300?image=101",
"https://unsplash.it/200/300?image=102"
];
function initSlideshow() {
setImage(0);
setInterval(function(){
nextImage();
},1000);
}
function nextImage() {
if(images.length === currentImage + 1){
currentImage = 0;
} else {
currentImage++;
}
setImage(currentImage);
}
function setImage(image) {
document.querySelectorAll('.slide')[0].src = images[image];
}
window.onload = initSlideshow();
Example: https://jsfiddle.net/vvbdwazc/
Currently, only image 3 is displayed. Anyone know what i'm doing wrong here?
it's all being displayed but the reason why you can only see the 3rd image is because you're not pausing for a certain time before displaying the next image hence it seems like it's not working.
use setInterval() method to show each image after a specified time.
Example:
var i=0;
var images = [];
images[0] = "images/1.jpg";
images[1] = "images/2.jpg";
images[2] = "images/3.jpg";
function changeImage () {
for(i=0; i < images.length; i++) {
document.slide.src = images[i];
}
}
var myVar = setInterval(function(){ changeImage() }, 1000);
You may later wish to prevent the setInterval() method from executing any longer in that case have a look at clearInterval().
window.onload = changeImage; tells me you want to change the image on page load event? In other words, the image changes only upon page load (or refresh).
Since state is not maintained by default (eg local storage or session storage or cookies) your best bet would be to use a random generator to choose randomly. See Generating random whole numbers in JavaScript in a specific range?
This is because the for works so fast it gets quickly to the third image. You could use instead some setInterval like this:
<img id="slide" width="300" height="300">
<script>
var images = [];
images[0] = "images/1.jpg";
images[1] = "images/2.jpg";
images[2] = "images/3.jpg";
var i = 0;
setInterval(function() {
var slide = document.querySelector("#slide"); //Select the img element by ID
slide.src = images[i++];
if(i > images.length - 1)
i = 0;
}, 1000); //Time in milliseconds
</script>
This will change constantly back to the first image when it reaches the last one.
Edit: Forgot to mention. setInterval works like a "repeater", it will work indefinitely until you clear it. To clear it you need to asign it to a variable and then use clearInterval passing the variable.
var interval = setInterval(function(){}, 1000) //example
clearInterval(interval);
Like so.
