var step = 1;
var delay = 80; 
var Hoffset = 0;
var Woffset = 0;

var xPos = 2;
var yPos = 700;
var yon = 0;
var xon = 1;
var xStartPos = 1;
var xEndPos = 20;
var img = document.getElementById('img1');

var xPosR = 900;
var yPosR = 5;
var yonR = 1;
var xonR = 0;
var xStartPosR = 893;
var xEndPosR = 910;
//var imgR = document.getElementById('img2');
var imgAbs = document.getElementById('imgAbs');

function changePosL() 
{
img = img;
width = document.body.clientWidth;
height = document.body.clientHeight;
Hoffset = img.offsetHeight;
Woffset = img.offsetWidth;

img.style.left = xPos;// + document.body.scrollLeft;
img.style.top = yPos ;//+ document.body.scrollTop;
if (yon) {
yPos = yPos + step;
}
else {
yPos = yPos - step;
}
if (yPos < 0) {
yon = 1;
yPos = 0;
}
if (yPos >= (height - Hoffset)) {
yon = 0;
yPos = (height - Hoffset);
}
if (xon) {
xPos = xPos + step;
}
else {
xPos = xPos - step;
}
if (xPos < xStartPos) {
xon = 1;
xPos = xStartPos;
}
if (xPos >= xEndPos) {
xon = 0;
xPos = xEndPos;
   }

//imgR.style.left = xPosR ;//+ document.body.scrollLeft;
//imgR.style.top = yPosR ;//+ document.body.scrollTop;
imgAbs.style.left = xPosR ;//+ document.body.scrollLeft;
imgAbs.style.top = yPosR + 45 ;//+ document.body.scrollTop;
if (yonR) {
yPosR = yPosR + step;
}
else {
yPosR = yPosR - step;
}
if (yPosR < 0) {
yonR = 1;
yPosR = 0;
}
if (yPosR >= (height - Hoffset)) {
yonR = 0;
yPosR = (height - Hoffset);
}
if (xonR) {
xPosR = xPosR + step;
}
else {
xPosR = xPosR - step;
}
if (xPosR < xStartPosR) {
xonR = 1;
xPosR = xStartPosR;
}
if (xPosR >= xEndPosR) {
xonR = 0;
xPosR = xEndPosR;
   }

}

function start() {
img.visibility = "visible";
setInterval(function(){fun=changePosL();}, delay);
}
start();