Dynamic Images, Events, and the DOM

Overview
Most Web sites have images. There are many different features and functionality that can be used to work
with images via the use of JavaScript. These include preloading, rollovers, and cycling banner ads. In this
assessment, you will be working with JavaScript, images, and events, and you will be manipulating the
DOM to create an interactive image gallery.
Hint: Preloading your images will only work on a hosting server and not your local drive as there’s no load
time for your images locally. Once you have preloaded those images, you may want to clear your cache to
test your loading of the images again.
Tip: In a smaller JavaScript program such as this one, each function is created for a specific purpose.
However, in more complex sites, it is better to build functions that we can apply to multiple situations. For
example, rather than specifying an element name or id, we can use a variable that is passed into the function.
Directions
Use the gallery.html and index.html files that you downloaded in the Zip file in Assessment 1. Create
functionality using JavaScript on the following pages:
index.html
Preload the images (banner1.jpg, banner2.jpg and banner3.jpg found in the images folder) for the banner at
the top of the page.
Create a cycling two-state banner that cycles every three seconds.
gallery.html
Preload the gallery images.
Create rollover functionality for each of the thumbnails in your image gallery. Use appropriate images found
in the images folder.
Write developer comments to describe the variables being declared and explain the functions and logical
blocks of JavaScript code pertaining to the gallery.
Make sure to do the following:
Create an onpageload function to preload all of your images.
Create a modularized function to cycle the homepage banner.
Create a modularized rollover function for gallery images.
Once completed, view your pages in each of your two selected Web browsers to see if the content renders
appropriately and consistently within each. Next, verify that your code is error-free using the appropriate
browser-specific development tool found in the Resources. Take a screen capture of each of your validation
results and save it for submission.
Note: “Modularized” refers to creating components that can be re-purposed without significant changes to
coding. Modularized components have no “hard coding” of image names, urls, et cetera, in the functions.
There is an example JavaScript modularized and non-modularized JavaScript found in the Suggested
Resources in the file called “Example Code.”

Submission Requirements
Upload your Web site files to your Web host.
Submit your work in the courseroom using a single Zip file containing the following:
Your entire Web site including all associated files.
A Word document with:
The url to your Web site so faculty can view your site on a live host.
A screen capture of each of your two validations that you completed using the developer tools found in the
Resources.