Question from JavaScript image slider.

Question

Code is inserted below.
Why there is so much of lag while click on the prev button ? What are the errors in the code.. Can anybody answer me.
https://code.sololearn.com/W5QijUn3LIoO/?ref=app

Answer 1

I did some modifications to your code ,not sure if you wanted this way but here it is
var num = 0;
var x=document.getElementById("btn1");
var y="click";
btn1.addEventListener(y,next);
function next() {
var slider = document.getElementById('slider');
num++;
if(num < images.length) {
slider.src = images[num];
}
else{
num=0;
slider.src=images[num];
}
}
var a =document.getElementById("btn2");
var b="click";
btn2.addEventListener(b,prev);
function prev() {
var slider = document.getElementById('slider');
num--;
if(num >=0) {
slider.src=images[num];
}
else
{
num=2;
slider.src=images[num];
}
}
}

Answer 2

Ajitha G R it's working fine with every image showing up

Answer 3

First image is at 0 index when you click next index is still 0 ,so nothing happens and later n becomes 1

Answer 4

you should num-- in prev()

and check if num becomes smaller than 0

https://code.sololearn.com/WsG7OrVX5P81/?ref=app

Answer 5

Abhay .sry, Yes it is working...Thank you👍👍

Answer 6

Abhay In function next(), n++ is placed before the if statement,
So n=1, o/p will be,
slider.src=images[1];it is not starting from 0,though it is correct and giving proper result.
If I placed n++ inside the if statement like this👇,
If(num<images.length){
slider.src=images[num];. // images[0]
num++;
}
I need to click twice to slide the first image.why?
what is the reason?

Answer 7

OK..Got it

Answer 8

Gordon Thank you for replying.😊
but I used slightly different logic than what is already given in lesson.i checked your code ,it is not working.