function open_center(thislayer, thispos){
	
	// Script fŸr Netscape
	if (is_nav){
		if (is_nav4up) {
		   	var layerRef="document.layers";
	 	   	var styleSwitch="";
		}
		if (is_nav6up){
			var layerRef="document.getElementById";
	    		var styleSwitch=".style";
	  	}	

		// Berechnung der Mitte
		var breite = window.innerWidth;
		var hoehe = window.innerHeight;
		var left = thispos;
		
		if (breite > 776){
			var tbreite = breite - 776;
			tbreite = tbreite /2;
			left = left + tbreite;
			
		} // if breite

		if (is_nav6up) {
			document.getElementById(thislayer).style.left = left;
		}
		else {
			left = left - 10;
			eval(layerRef+'["'+thislayer+'"]'+styleSwitch+'.left="'+left+'"');
		}
	}


	// Script fŸr IE
	
	else if (is_ie) {
		var breite = document.body.offsetWidth;
		var left =thispos;
		if (is_win) left = left- 10;
		if (breite > 776){
			var tbreite = breite - 776;
			tbreite = tbreite /2;
			left = left + tbreite;
			document.all[thislayer].style.left=left;
		}
	}
}