var _t1 = 0; //ҳʱȴͼƬʱ䣬λΪ룬Ϊ0
var _t2 = 3; //ͼƬתļʱ
var _tnum = 5; //ͼ
var _tn = 1;//ǰ,
var _tl =null;
_tt1 = setTimeout('change_img()',_t1*1000);
function change_img(){
setFocus(_tn);
_tt1 = setTimeout('change_img()',_t2*1000);
}
function setFocus(i){
if(i>_tnum){_tn=1;i=1;}
_tl?document.getElementById('focusPic'+_tl).style.display='none':'';
document.getElementById('focusPic'+i).style.display='block';
_tl=i;
_tn++;
}