Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

Javascript Index Array Variable

Posted on 2013-10-23
1
Medium Priority
?
508 Views
Last Modified: 2013-11-19
Hello expert,

Thanks to COBOL Dinasaur for helping me to get the JavaScript to work.
Code attached.

These are statements I believe to be true. Correction or comments
solicited.

In the line right after the array is listed is the statement "i=0;". Was not sure
what this was for. So I removed it and the script broke. I thought it was defining
the variable i. So it tried   "var i=0;" and it still worked. So my surmise is "i=0;" defines the index variable i and sets it to zero.
So I tried "i=2; and the screen started red and then went to yellow.
So the line
 i=(i>=colors.length) ? 0 : i+1;
is taking the array index number and incrementing it. It starts with zero (red),
then takes the index variable i, which is set to two (green)  and kicks it up a
notch to three (yellow). Thats why with i set to two the screen goes red, yellow.
Also the reason it always starts with red is the script is set to do that with
document.body.style.backgroundColor = colors[0];
This was proved by changing the array number from zero to two which makes the screen
begin green.

Question

I thought that the script would loop thru the colors and stop. The reason
it does not stop is the conditional statement    
 i= (i>=colors.length) ? 0 : i+1;
says if the index var (i) is greater than the length of the array then
set the index var back to zero If the index var is not greater
than the length of the array then increment the index var.

Actually I think I just proved this is true. If the conditional is
removed and  
i= (i>=colors.length) ? 0 : i+1;
is substituted with
i = i+1
then the screen starts with red loops thru the colors and stops with
purple.

Ok. So I answered my own question. Often it is by thinking about
a system long enough to ask a logical question that the answer
is discovered. If you have any comments I am still interested.

Thanks again.

Allen in Dallas
change-k.html
0
Comment
Question by:Allen Pitts
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 14

Accepted Solution

by:
Pierre Cornelius earned 2000 total points
ID: 39596429
lol, why ask the question if you already answered it yourself. You should request a delete and refund of this question.
0

Featured Post

Build and deliver software with DevOps

A digital transformation requires faster time to market, shorter software development lifecycles, and the ability to adapt rapidly to changing customer demands. DevOps provides the solution.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In threads here at EE, each comment has a unique Identifier (ID). It is easy to get the full path for an ID via the right-click context menu. However, we often want to post a short link within a thread rather than the full link. This article shows a…
Ready to get certified? Check out some courses that help you prepare for third-party exams.
This video teaches users how to migrate an existing Wordpress website to a new domain.
The is a quite short video tutorial. In this video, I'm going to show you how to create self-host WordPress blog with free hosting service.

722 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question