var count = 0;
var baseuri; //各ページ内で設定 例: baseuri = '/show/image'
var imageLength; //各ページ内で設定 例: imageLength = 3

var imagePrefix; // 必要に応じて設定 例: var imagePrefix = "photo2_";
if (imagePrefix == null) {
	imagePrefix = "photo";
}

prImg= new Array();
/*
for (i=0; i<imageLength; i++){
	prImg[i] = new Image();
	prImg[i].src = baseuri + "/" + imagePrefix + (i+1) + ".jpg";
}
*/
		
function isSafari() {
	var userAgent = navigator.userAgent;
	return (userAgent.indexOf("Safari")!=-1);
}

function next(){

	count ++;
	document.getElementById("slidePhoto").src = baseuri + "/" + imagePrefix + (count+1) + ".jpg";
	document.getElementById("previousDisplay").style.visibility = "visible";

	preload(count+2);

	// safari bug fix
	if (isSafari()) {
		document.getElementById("slidePhoto").width = prImg[count].width;
		document.getElementById("slidePhoto").height = prImg[count].height;
	}
		
	if(count+1 == imageLength){
		document.getElementById("nextDisplay").style.visibility = "hidden";
	}else{
		document.getElementById("nextDisplay").style.visibility = "visible";
	}
		
}
	
	
function previous(){
	count --;
	document.getElementById('slidePhoto').src = baseuri + "/" + imagePrefix + (count+1)  + ".jpg";		
	document.getElementById("nextDisplay").style.visibility = "visible";
		
	// safari bug fix
	if (isSafari()) {
		document.getElementById("slidePhoto").width = prImg[count].width;
		document.getElementById("slidePhoto").height = prImg[count].height;
	}

	if(count == 0){
		document.getElementById("previousDisplay").style.visibility = "hidden";
	}else{
		document.getElementById("previousDisplay").style.visibility = "visible";
	}
}

// count = n枚目
function preload(count) {

	if (count > imageLength) {
		return;
	}
	
	prImg[count-1] = new Image();
	prImg[count-1].src = baseuri + "/" + imagePrefix + count + ".jpg";
}
		
document.write("<div class=\"pageNavigation\">");
document.write("<div class=\"previous\" id=\"previousDisplay\" style=\"visibility: hidden;\"><a href=\"javascript:previous();\"><span>前へ</span></a></div>");
document.write("<div class=\"next\" id=\"nextDisplay\"><a href=\"javascript:next();\"><span>次へ</span></a></div>");
document.write("</div>");
	
preload(1);
preload(2);