How to Create a Simple Image Slider in JavaScript?

Dear Friends,

In this Article i am going to explain about creating a simple slider in JavaScript. So let us start step by Step tutorial on How to create a simple image slider in JavaScript. Before starting this Example you should know the following topics.

What is JavaScript Arrays & How to Populate arrays in JavaScript?

What is meant by Set Interval and Clear Interval in JavaScript?

How to change image source dynamically with JavaScript?

If you are not clear about the above mentioned topics, I strongly suggest you to please go through the above mentioned topics first. If you know above topics, let is start the example.

Step 1:-

Create a simple HTML Template as Follows with Image element with id "myImg" in it.

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>
<body>
    <img src="" id ="myImg">
</body>
</html>

Step 2:-
Now add a simple array which contains list of objects with image name as follows.

<script type="text/JavaScript">
var images=[{name:"images/1.jpg"},{name:"images/2.jpg"},{name:"images/3.jpg"},{name:"images/4.jpg"},
{name:"images/5.jpg"},{name:"images/6.jpg"}]
var imgNo=0;
</script>

Step 3:-
Now Let us create a simple function called "startSlide" as follows.

function startSlide(){
    document.getElementById("myImg").setAttribute("src",images[imgNo].name);
        if(imgNo==5){
            imgNo=0
        }
        else{
           imgNo++;
    }
 }

When we invoke the function "startSlide" , it will access the image element with id "myImg" .At this point of time this this element is not having any value for the "src" Attribute . Now we will assign src attribute value as "images[imgNo].name". Since we have assigned a value for imgNo as 0 , it will assign the first objects name as image src .

In Result Now the first image will be appearing. After that it will come to that if condition to check the image no. If the image no is 5, it means we have reached to the last image. Since we don’t have any images after that we will assign imgNo=0. So it will reach to the first image once again.

Step 4:-

Now we have to create a function which will invoke the above startSlide in 1 sec interval. (You can change the interval as per your wish). So the no-load function will look like this.

window.onload=slide();
function slide(){
    autoSlide=setInterval(startSlide,1000);
}

Step 5:-

Now when we run, our Image sliding application is ready and running. we need to do some more things .When we mouse over on the image , sliding has to stop and when we mouse out , sliding has to start once again . To od that we need to add the following code.

document.getElementById("myImg").onmouseover=function (){
            clearInterval(autoSlide)
        }

        document.getElementById("myImg").onmouseout=function (){
            slide()
        }

So here is final Code Look Like:

<!DOCTYPE html>
<html>
<head>
    <title></title>
    <style type="text/css">
        img#myImg {
    width: 900px;
    height: 600px;
}
    </style>
</head>
<body>
    <img src="" id="myImg">
    <script type="text/javascript">
    var autoSlide;
        var images=[{name:"images/1.jpg"},{name:"images/2.jpg"},{name:"images/3.jpg"},{name:"images/4.jpg"},{name:"images/5.jpg"},{name:"images/6.jpg"}]
        window.onload=slide();
        function slide(){
            autoSlide=setInterval(startSlide,1000)
        }
        var imgNo=0;
        function startSlide(){
            document.getElementById("myImg").setAttribute("src",images[imgNo].name);
            if(imgNo==5){
                imgNo=0
            }
            else{
                imgNo++;
            }
        }
        document.getElementById("myImg").onmouseover=function (){
            clearInterval(autoSlide)
        }
        document.getElementById("myImg").onmouseout=function (){
            slide()
        }
    </script>
</body>
</html>

About Author:-

I have come across so many difficult situations while learning JavaScript. I thought I can share my experience in my blog http://blog.sunlineitsolutions.com/ to the people which may be helpful for them.