var iImgArr=[""];//预加载图像

function preLoadImage(imgArr)
{
    var img=new Image();
    for(var i=0;i<imgArr.length;i++)
    {
       img.src=imgArr[i].replace("Photo/","Photo/Sm");          
    } 
}

function swapImage(boardId,imgArr,imgIdx,timeout,linkId)
{
    var board=document.getElementById(boardId);
    var link=document.getElementById(linkId);
    var nextIdx=imgIdx;
    var str=board.parentNode.id.substring(0,4);

    if(str=="true")
    {
       board.src=imgArr[imgIdx].replace("Photo/","Photo/Sm");
       link.href=imgArr[imgIdx];
       board.alt=imgIdx;
       nextIdx=++imgIdx>imgArr.length-1?0:imgIdx;
       
       //淡化切换
       if(imgArr.length>1)
       {
            board.style.opacity=0;
            board.style.filter = "Alpha(Opacity=0)"; 
            setOpacity(board.id, 0); 
       }
    }

    setTimeout(getSwapFunction(boardId,imgArr,nextIdx,timeout,linkId),timeout);
}
    //获得下一次切换图片的方法
function getSwapFunction(boardId,imgArr,imgIdx,timeout,linkId)
{
    var swapFunction=function()
    {
       swapImage(boardId,imgArr,imgIdx,timeout,linkId);
    };
    return swapFunction;
}

function preLoadImage1(imgArr)
{
    var img=new Image();
    for(var i=0;i<imgArr.length;i++)
    {
       img.src=imgArr[i].replace("Photo/","Photo/Sm");          
    } 
}
//切换图片
function swapImage1(boardId,imgArr,imgIdx,timeout,linkId)
{
    var board=document.getElementById(boardId);
    var link=document.getElementById(linkId);
    var nextIdx=imgIdx;
    var str=board.parentNode.id.substring(0,4);

    if(str=="true")
    {
       board.src=imgArr[imgIdx].replace("Photo/","Photo/Sm");
       link.href=imgArr[imgIdx];
       board.alt=imgIdx;
       nextIdx=++imgIdx>imgArr.length-1 ? 0 : imgIdx;
       
       //淡化切换
       if(imgArr.length>1)
       {
            board.style.opacity=0;
            board.style.filter = "Alpha(Opacity=0)"; 
            setOpacity(board.id, 0,timeout); 
       }

    }
    setTimeout(getSwapFunction1(boardId,imgArr,nextIdx,timeout,linkId),timeout);
}
//获得下一次切换图片的方法
function getSwapFunction1(boardId,imgArr,imgIdx,timeout,linkId)
{
    var swapFunction1=function()
    {
       swapImage1(boardId,imgArr,imgIdx,timeout,linkId);
    };
    return swapFunction1;
}
//淡化切换
function setOpacity(id, opacity,timeout) 
{
    var obj = document.getElementById(id); 
    if (obj) 
    { 
        obj.style.opacity = opacity / 100; 
        obj.style.filter = "Alpha(Opacity="+ opacity +")"; 
        if (opacity <100) 
        { 
            setTimeout(("setOpacity('" + id + "', " + Math.min(opacity+10,100) + ")"),100); 
        }
    } 
}