what does the % symbol do?

[atomicmunky]

does anyone know what the % percent symbol does in javascript? or how it is used?

i've searched all over the place online and looekd a coupld of books that i have but i can't seem to find an answer.

[Drew630]

It finds the remainder in a division.

i.e. 10%2 = 0
5%2 = 1

Most often it is used to findout if a number is even or odd.

var num as whatever

if (num%2 == 0) { number is even }
else { number is odd }

Hope that helps

Drew

[creole]

Fantastic answer Drew!

Kudos for your help.

[Vincent Puglia]

Hi,

As Drew said, the modulos (sp?) '%' operator returns the remainder of a division.

Another use is to get a pseudo-random number:

var numOfBanners = 4;
var seed = new Date().getSeconds()
var bnr2show = seed % numOfBanners;

the above lines are from the "Reading Banner Data from a File" script/tutorial at my site. They are used instead of a random function. the bnr2show var is used to access elements within an array

Vinny

[atomicmunky]

thanks all very much.
the way i was seeing it get used was like this:

var NumberOfImages = 10;
var now = new Date()
var sec = now.getSeconds()
var ImageNumber = sec % NumberOfImages;
ImageNumber +=1;
if (ImageNumber==1)
{
 url="portfolio.html";
 Graphic="images/image.jpg";
 width = "250"
 height = "250"
}
if (ImageNumber==2)



etc, etc up to 10 ...



document.write('<a href=\"' + url + '\">');
document.write('<img src=\"' + Graphic + '\" width=');
document.write(width + ' height=' + height + ' ');
document.write('border=0><br>');
document.write('</a>');

so i guess that would display a different image depending on the time but i couldn't figure out how the modulos fit into the whole equation.

it looks similar to your code Vinny.
thanks again.

[Vincent Puglia]

Hi chris,

That it does. The difference is that you are adding 1 to the result and then using if/else statements (which are probably all the same except for the image information itself). You might consider placing everything into an array:

var imgInfo=new Array()
imgInfo[0]="portfolio.html|images/image.jpg|250|250";
...etc...

then you can access the data as follows:

var imgDataArray = imgInfo[imageNumber].split("|")

that would give you the following array:
imgDataArray[0] = 'portfolio.html'
imgDataArray[1] = 'images/image.jpg'
imgDataArray[2] = '250'
imgDataArray[3] = '250';

Vinny

[atomicmunky]

ok, how does the value of 'image.jpg' change then?
what i mean is that there would be image1.jpg, image2.jpg all the way to image10.jpg.

wouldn't i need to add a counter to increment image.jpg?

[Vincent Puglia]

Hi,

If you have ten images, each would be in (above example) in the second cell of the main array (imageInfo): imgDataArray[1] = 'images/image.jpg'


so you would declare your array:
imgInfo[0]="...html|images/image1.jpg|...";
imgInfo[1]="...html|images/image2.jpg|...";
imgInfo[2]="...html|images/image3.jpg|...";

(note the cell reference is one less than the image number; but that's because I'm basing it upon what you said originally)
and then, using your code:

var NumberOfImages = 10;
var now = new Date()
var sec = now.getSeconds()
var ImageNumber = sec % NumberOfImages;
var imgDataArray = imgInfo[ImageNumber].split("|")

imgDataArray now holds the random image you wanted. If you wanted a specific image you would simply say:
var imgDataArray = imgInfo[aNumberFrom_0_to_9].split("|")

One of the following scripts at my site should use and explain the above methods: "Reading Banner Data..." or "Reading Data from a File."

Vinny