// JavaScript Document
////////////////////////////////////////////////////////////////////
//////////////////////copyright by Nicho-Yao/////////////////////////
////////////////////////////////////////////////////////////////////
var ImgPage = function(boxId,//li的容器ID
					   lBtnId,//上一页按钮ID
					   rBtnId,//下一页按钮ID
					   numBoxId,//显示页数容器ID
					   pageNum){//每页显示个数
	var box = document.getElementById(boxId);
	var lBtn = document.getElementById(lBtnId);
	var rBtn = document.getElementById(rBtnId);
	var numBox = document.getElementById(numBoxId);
	numBox.innerHTML = "1/1";
	var theLength = box.getElementsByTagName("li").length;
	var liArr = new Array();
	var nowPlay = 0;
	var pageTotal = 0;
	for(var a = 0; a < theLength; a ++){
		var theLi = box.getElementsByTagName("li")[a];
		liArr.push(theLi);
	}
	
	if(liArr.length % 3 != 0){
		pageTotal = Math.floor(liArr.length / 3) + 1;
	}else{
		pageTotal = liArr.length / 3;
	}
	
	var changePlay = function(num){
		nowPlay = num;
		for(var b = 0; b < theLength; b ++){
			if(b >= nowPlay * pageNum && b <= nowPlay * pageNum + 2){
				if(liArr[b].style.display == "none") liArr[b].style.display = "block";
			}else{
				if(liArr[b].style.display != "none") liArr[b].style.display = "none"; 
			}
		}
		numBox.innerHTML = (nowPlay + 1) + " / " + pageTotal+" 页 " 
	}
	
	var lBtnClickHandler = function(){
		if(nowPlay > 0){
			changePlay(nowPlay - 1);
		}
	}
	var rBtnClickHandler = function(){
		if(nowPlay < pageTotal - 1){
			changePlay(nowPlay + 1);
		}
	}
	if(pageNum <= theLength){
		lBtn.onclick = function(){lBtnClickHandler();};
		rBtn.onclick = function(){rBtnClickHandler()};
		changePlay(nowPlay);
	}
}