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View Full Version : Slideshow Help



stilts
01-23-2012, 05:12 PM
var mySlideShow = document.getElementById("slideShow");

var imageArray=new Array();
imageArray[0]="url(images/Slide1.JPG)";
imageArray[1]="url(images/Slide2.JPG)";
imageArray[2]="url(images/Slide3.JPG)";


var imageIndex = 0;

var leftArrow = document.getElementById("left");
var rightArrow = document.getElementById("right");

mySlideShow.style.backgroundImage = "url(images/Slide1.JPG";


function changeRight () {

mySlideShow.style.backgroundImage = imageArray[imageIndex];
imageIndex++;


if (imageIndex >= imageArray.length) {
imageIndex = 1;



}

console.log(imageIndex);

}


function changeLeft () {

mySlideShow.style.backgroundImage = imageArray[imageIndex];
imageIndex--;
console.log(imageIndex);

}




rightArrow.onclick = function() {

changeRight();

}

leftArrow.onclick = function() {

changeLeft();

}




So what I am trying to do here is basically a slideshow. When I click on the left button it goes backwards and when I click the right button it goes forward. The problem arises when I click on the left arrow. It doesn't act as I want it to and I need some help. I want to remove one from the image index but imageindex--; doesn't seem to work.

Any help would be awesome.

Logic Ali
01-23-2012, 06:00 PM
Your 'right' function sets the image using the current value of imageIndex, suggesting that it won't do anything the first time it is used. Also it should set imageIndex to 0 on overflow not 1. The 'left' function makes no attempt to check for underflow. You should change ( and if necessary reset ) the value of imageIndex before setting the image.

stilts
01-23-2012, 07:43 PM
In the right function how do I set the current image to suggest that it would be doing something the first time it is used?

How do I check for underflow?

What do you mean by reset the value before setting the image?

Sorry I am new to programming in general so I hope you can bare with me.



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