function getversion()
{
    var browser=navigator.appname;
    var b_version=navigator.appversion;
    var version=b_version.split(";");
    var trim_version=version[1].replace(/[ ]/g,"");
    return (browser=="microsoft internet explorer" && trim_version=="msie10.0");
}

function imagechangenews(uid, width, height, interval, duration, btitle, bsummary, zoomtype, zoomout, iscentercutimg, cutimgparent)
{
    var _this = this; //把this保存下来，以后用_this代替this，这样就不会被this弄晕了

    _this.imgs = new array(); //图片组
    _this.urls = new array(); //链接组
    _this.titles = new array(); //标题组
    _this.summarys = new array(); //摘要组
    _this.tiptitles = new array(); //鼠标提示
    
    _this.nextindex=0;   //下次显示的滚动图
    _this.currentindex=-1;   //当前显示的滚动图
    _this.firstflag = 0;  //标识是否为第一次开始执行
    _this.currenttimer = null;     //标识作用
    
    //图片加载完毕事件
    _this.onimgload = function(loadindex)
    {
        _this.imgs[loadindex].setattribute("loadedflag", true);
        if(loadindex == _this.currentindex)
        {
            _this.constrainimg(document.getelementbyid(uid + "pic"), _this.imgs[loadindex], document.getelementbyid(uid + "imgdiv"));
        }
    }   
    
    //添加图片
    _this.addimg = function(img, url, title, summary,tiptitle)
    {
        var imgcount = _this.imgs.length;
        _this.imgs[imgcount] = new image();
        
        _this.imgs[imgcount].onload = function(){_this.onimgload(imgcount)};
        
        _this.imgs[imgcount].src = img;
        
        _this.urls[imgcount] = url;
        _this.titles[imgcount] = title;
        _this.summarys[imgcount] = summary;
        if(tiptitle){
            _this.tiptitles[imgcount] = tiptitle;
        }
    }

    //触发图片改变
    _this.changeimg = function (n)
    {       
        if(_this.imgs.length < 1)
        {       
            return;       
        }       
        
        if(_this.currenttimer != null)
            window.clearinterval(_this.currenttimer); //清除用于循环的currenttimer  
        
        _this.currenttimer = window.setinterval(_this.onchangeimg, interval * 1000);//设置循环周期为4000
        
        _this.nextindex = n; //要显示的id等于传入的n值,
        _this.onchangeimg();
    }
    
    //改变图片操作
    _this.onchangeimg = function()       
    {
        try
        {
             if(_this.imgs.length < 1)
             {       
                 return;       
             }     
             if(_this.firstflag == 0)
             {
                _this.firstflag = 1;
             }       
             else if(document.all && !getversion())
             {
                 var imgfilter = document.getelementbyid(uid + "div").filters[0];
                 imgfilter.apply();
                 imgfilter.play(duration);
                 imgfilter.transition=23;
             }
             //图片未加载完毕
             if(_this.imgs[_this.nextindex].getattribute("loadedflag") == null)
             {
                document.getelementbyid(uid + "pic").src = "/system/resource/images/space.gif";
             }
             else
             {
                //图片正常加载, 设置图片
                _this.constrainimg(document.getelementbyid(uid + "pic"), _this.imgs[_this.nextindex], document.getelementbyid(uid + "imgdiv"));
             }
             //设置当前图片编号
             _this.currentindex = _this.nextindex;
             
             
             document.getelementbyid(uid + "url").href = _this.urls[_this.nextindex];
			
			 btitle = true;
             if(btitle)
             {       
                 document.getelementbyid(uid + "newstitle").innerhtml = _this.titles[_this.nextindex];
                 
                 document.getelementbyid(uid + "newstitle").href = _this.urls[_this.nextindex];
                 if(_this.tiptitles.length > 0){
                     document.getelementbyid(uid + "newstitle").title =_this.tiptitles[_this.nextindex];
                 }else{
                     document.getelementbyid(uid + "newstitle").title =_this.titles[_this.nextindex];
                 }

             }       
             if(bsummary)
             {
                 document.getelementbyid(uid + "newssummary").innerhtml = _this.summarys[_this.nextindex];
                 document.getelementbyid(uid + "newssummary").href = _this.urls[_this.nextindex];
             }       
             //设置所有按钮的样式
             for(var i = 0;i < _this.imgs.length; i++)
             {       
                  if(i == _this.nextindex)
                    document.getelementbyid(uid + "selectnode"+i).classname='imagechangenews_fnode';
                  else
                    document.getelementbyid(uid + "selectnode"+i).classname='imagechangenews_pnode';
             }       
             _this.nextindex++;       
             if(_this.nextindex >= _this.imgs.length)
             {
                //如果id大于总图片数量。则从头开始循环       
                _this.nextindex = 0;       
             }       
        }
        catch(e)
        {
        }
    }
    
    //等比例设置图片
    _this.constrainimg = function(imgobj, imagevar, imgdiv)
    {
        try
        {
            var widthrate = imagevar.width / width;
            var heightrate = imagevar.height / height;
            var imgwidth = 0;
            var imgheight = 0;

            if(widthrate > 1 || heightrate > 1) //图片过大时
            {
                if(!iscentercutimg) {
                    if (zoomtype)//按比例缩小
                    {
                        var rate = math.max(widthrate, heightrate);
                        imgwidth = math.max(1, math.min(imagevar.width / rate, width));
                        imgheight = math.max(1, math.min(imagevar.height / rate, height));
                    }
                    else//拉伸
                    {
                        imgwidth = width;
                        imgheight = height;
                    }
                }
            }
            else if(widthrate < 1 || heightrate < 1) //图片小
            {
                if(!iscentercutimg) {
                    if (zoomout)//自动放大
                    {
                        if (zoomtype)//按比例放大
                        {
                            var rate = math.max(widthrate, heightrate);
                            imgwidth = math.max(1, math.min(imagevar.width / rate, width));
                            imgheight = math.max(1, math.min(imagevar.height / rate, height));
                        }
                        else //拉伸
                        {
                            imgwidth = width;
                            imgheight = height;
                        }

                    }
                    else {
                        imgwidth = imagevar.width;
                        imgheight = imagevar.height;
                    }
                }
            }
            else //大小合适
            {
               imgwidth = width;
               imgheight = height;
            }

            imgobj.src = imagevar.src;
            if(!iscentercutimg) {
                imgobj.width = imgwidth;
                imgobj.height = imgheight;
                imgdiv.style.paddingtop = (height - imgheight) / 2+"px";
            }else{
                cutimg(imgobj,"autocut",cutimgparent);
            }
        }
        catch(e)
        {
        }
    }
}