var imgWidth=1000, imgHeight=750;	// Bild-Maße
var xAbs=-170, yAbs=150;			// absolute Position des Bildes zu Beginn
var x=250, y=0;						// relative Position des Ausschnitts zu Beginn
var clipWidth=750, clipHeight=100;	// Ausschnitts-Maße
//var restWidth=250, restHeight=650;  

function move() {
	document.getElementById("image").style.clip = 
		"rect("+y+" "+(x+clipWidth)+" "+(y+clipHeight)+" "+x+")";
	document.getElementById("image").style.left=xAbs;
	document.getElementById("image").style.top=yAbs;
}

function leftDown() {
	x--, xAbs++;
	y += 2; yAbs -= 2;
	move();
	if(y==500) {
		xAbs=-170, yAbs=150, x=250, y=0;
		setTimeout('leftDown()',1500);
	}
	else setTimeout('leftDown()',150);
}