function showpreview(zahl, direction, wmid){
	zahl = parseInt(zahl);
	var u = "";
	var alt_0 = "";
	var alt_1 = "";
	var alt_2 = "";
	var alt_3 = "";
	var neu = "";
		// xml archivabfrage
	switch (direction) {
  	case "back":
		VideoFileRequest('/ajax/getarchiv.ajax.php?camid=' + VidArray[zahl] + '&wmid=' + wmid, 0);
		zahl -= 1;
   		break;
 	case "neu":
		neu = alt_2;
		VideoFileRequest('/ajax/getarchiv.ajax.php?camid=' + VidArray[zahl] + '&wmid=' + wmid, 3);
		zahl += 1 ;
   		break;
	}
	
	
	
	var letzte = (VidArray.length)
	var zahlrechts = (zahl == letzte) ? 0 : zahl;
	var zahllinks = (zahl == 0) ? letzte-1: zahl;
	var links = "<img style=\"cursor:pointer;\" onclick=\"showpreview(\'" + zahllinks + "\', \'back\', \'" + wmid + "\'); return true;\" src=\"../images/pfeil-links.jpg\"/>";
	var rechts = "<img style=\"cursor:pointer;\" onclick=\"showpreview(\'" + zahlrechts + "\', \'neu\', \'" + wmid + "\'); return true;\" src=\"../images/pfeil-rechts.jpg\"/>";
	
	document.getElementById("links").innerHTML = links;
    document.getElementById("rechts").innerHTML = rechts;
}

function NewContent(neu, myid){
	document.getElementById(myid).innerHTML = neu;
}

function VideoFileRequest(seite, flag) {
	if (document.getElementById('requeststate'))
		document.getElementById('requeststate').innerHTML = '';
		myrequest = createRequest();
		if (myrequest) {
			if(flag == 3){
				myrequest.onreadystatechange = NextVideoProcessRequest;
			} else {
				myrequest.onreadystatechange = BackVideoProcessRequest;
			}
			myrequest.open('GET', seite, true);
			myrequest.send(null);
		}
}

function BackVideoProcessRequest() {
	var alt_0 = "";
	var alt_1 = "";
	var alt_2 = "";
	var alt_3 = "";
	var neu = "";
	if (document.getElementById('requeststate'))
		document.getElementById('requeststate').innerHTML = 'State: ' + myrequest.readyState;
	if (myrequest.readyState == 4) {
	if (document.getElementById('requeststatus'))
		document.getElementById('requeststatus').innerHTML = 'Status: ' + myrequest.status;
	if (myrequest.status == 200) {
		//document.write(myrequest.responseText);
		if (document.getElementById('prev_0'))
			alt_0 = document.getElementById('prev_0').innerHTML;
			alt_1 = document.getElementById('prev_1').innerHTML;
			alt_2 = document.getElementById('prev_2').innerHTML;
			document.getElementById('prev_0').innerHTML = myrequest.responseText;
			neu = document.getElementById('prev_0').innerHTML;
			if(neu != alt_0){
				NewContent(alt_2, 'prev_3');
				NewContent(alt_1, 'prev_2');
				NewContent(alt_0, 'prev_1');
			}
			//pausecomp(1000);
		}else {
			if (document.getElementById('prev_0'))
				document.getElementById('prev_0').innerHTML = 'Fehler! HTTP-Status: ' + myrequest.status;
		}
	}
}

function NextVideoProcessRequest() {
	var alt_0 = "";
	var alt_1 = "";
	var alt_2 = "";
	var alt_3 = "";
	var neu = "";
	if (document.getElementById('requeststate'))
		document.getElementById('requeststate').innerHTML = 'State: ' + myrequest.readyState;
	if (myrequest.readyState == 4) {
	if (document.getElementById('requeststatus'))
		document.getElementById('requeststatus').innerHTML = 'Status: ' + myrequest.status;
	if (myrequest.status == 200) {
		//document.write(myrequest.responseText);
		if (document.getElementById('prev_3'))
			
			alt_0 = document.getElementById('prev_0').innerHTML;
			alt_1 = document.getElementById('prev_1').innerHTML;
			alt_2 = document.getElementById('prev_2').innerHTML;
			alt_3 = document.getElementById('prev_3').innerHTML;
			document.getElementById('prev_2').innerHTML = alt_2;
			document.getElementById('prev_1').innerHTML = alt_1;
			document.getElementById('prev_0').innerHTML = alt_0;
			document.getElementById('prev_3').innerHTML = myrequest.responseText;
			neu = document.getElementById('prev_3').innerHTML ;
   			if(neu != alt_3){
				NewContent(alt_3, 'prev_2');
				NewContent(alt_2, 'prev_1');
				NewContent(alt_1, 'prev_0');
			}
			
		}else {
			if (document.getElementById('prev_3'))
				document.getElementById('prev_3').innerHTML = 'Fehler! HTTP-Status: ' + myrequest.status;
		}
	}
}


function pausecomp(millis) 
{
var date = new Date();
var curDate = null;

do { curDate = new Date(); } 
while(curDate-date < millis);
}