var xPos = 0;
var yPos = 0;
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;
var img = document.getElementById("img1");
img.style.top = yPos;
function changePos() {
    width=document.documentElement.clientWidth;
    height=document.documentElement.clientHeight;
    Hoffset=img.offsetHeight;   Woffset=img.offsetWidth;
    img.style.left=xPos+document.body.scrollLeft+"px";
    img.style.top=yPos+document.body.scrollTop+"px";
    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() {
    img.style.visibility="visible"; interval=setInterval('changePos()',delay);
}

function pause_resume(pause) 
{
	if(pause) 
	{
		clearInterval(interval);
	//	pause = false;
	}
	else 
	{
		interval = setInterval('changePos()',delay);
	//	pause = true; 
	}
}
start();