var xPos = 20;
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;
mylizi.style.top = yPos;

function changePos() {
width = document.body.clientWidth;
height = document.body.clientHeight;
Hoffset = mylizi.offsetHeight;
Woffset = mylizi.offsetWidth;
mylizi.style.left = xPos + document.body.scrollLeft;
mylizi.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 < 0) {
xon = 1;
xPos = 0;
}

if (xPos >= (width - Woffset)) {
xon = 0;
xPos = (width - Woffset);
   }
}

function start() {
mylizi.visibility = "visible";
interval = setInterval('changePos()', delay);
}

function pause_resume() {
clearInterval(interval);
/*if(pause) {
clearInterval(interval);
pause = false;
}

else {
interval = setInterval('changePos()',delay);
pause = true;
   }*/

}

start();