Img Altering sample code

i have been thinking writing url declartion inside javascript code caused me lots of time to search to update new image. so i change the wrong design and make use of alt tag which is text code base tagz. meaing i can store any text and convert into array.

Img declaration

img id 1

http://luck99.pw/png/mscene/security.png

img id 2 alt tags is written in array [x,x]

alt="[ 'http://luck99.pw/png/mscene/security.png' , 'http://luck99.pw/png/mscene/securitya.png']" src="http://luck99.pw/png/mscene/security.png"

img id 3 alt tags is written in array [x,x,x,x,x]

[ 'http://luck99.pw/png/mscene/security.png' , 'http://luck99.pw/png/mscene/securitya.png', 'http://www.luck99.pw/png/mscene/cleaner.png' , ' http://www.luck99.pw/png/mscene/janitor.png']

console output

with the above test output i can now control single image and not declare images url in javascript code and segregated. Now my javascript can pure code to pull img with sub img from its own tagz meaning i can use alt tagz array properties and call imgid3.alt[1] or [2] to swap picture So i will code

Swaping

var testarray2=new Array();
testarray2=eval(document.all.imgid3.alt);

var testnum=0;

function callswapmg()
{
imgid3.src= testarray2[testnum];
testnum++;
if(testnum >=testarray2.length)
{testnum = 0;}
}

img id 4 alt tags is written in array [x,x,x,x,x] [ 'http://luck99.pw/png/mscene/security.png' , 'http://luck99.pw/png/mscene/securitya.png', 'http://www.luck99.pw/png/mscene/cleaner.png' , ' http://www.luck99.pw/png/mscene/janitor.png']