function changePoslt() {

widthlt = document.body.clientWidth;
heightlt = document.body.clientHeight;
Hoffsetlt = imglt.offsetHeight;
Woffsetlt = imglt.offsetWidth;
imglt.style.left = xPoslt + document.body.scrollLeft;
imglt.style.top = yPoslt + document.body.scrollTop;
/*if (yonlt) {
yPoslt = yPoslt + step;
}
else {
yPoslt = yPoslt - step;
}
if (yPoslt < 0) {
yonlt = 1;
yPoslt = 0;
}
if (yPoslt >= (heightlt - Hoffsetlt)) {
yonlt = 0;
yPoslt = (heightlt - Hoffsetlt);
}
if (xonlt) {
xPoslt = xPoslt + step;
}
else {
xPoslt = xPoslt - step;
}
if (xPoslt < 0) {
xonlt = 1;
xPoslt = 0;
}
if (xPoslt >= (widthlt - Woffsetlt)) {
xonlt = 0;
xPoslt = (widthlt - Woffsetlt);
}*/
}



function start() {
//img.visibility = "visible";
imglt.style.visibility = "visible";
//interval = setInterval('changePos()', delay);
interval = setInterval('changePoslt()', delay);
}

//*******************************************************************

var xPoslt = 5;
var yPoslt = 400;     
var xPos = 20;
var heightlt= 0;
var Hoffsetlt= 0;
var Woffsetlt= 0;
var yonlt= 0;
var xonlt= 0;

var yPos = document.body.clientHeight;
var step = 1;
var delay = 30; 
var height = 0;
var Hoffset = 0;
var Woffset = 0;
var yon = 0;
var xon = 0;
var pause = true;
var interval;
//img.style.top = yPos;
imglt.style.top = yPoslt;
  start()