网页出现这个错误，不知道怎么回事

请你们帮我看看，怎么回事。

var CurrentHotScreen = 0 ;
function setHotQueryList(screen){
        var Vmotion = "forward" ;
        var MaxScreen = 4 ;
        if (screen >= MaxScreen) {
                screen = 0 ;
                Vmotion = "reverse" ;
        }
        cleanallstyle();
        document.getElementById("focuss_"+screen).className = "up" ;
  for (i=0;i<MaxScreen;i++) {
        document.getElementById("switch_"+i).style.display = "none" ;
  }
  document.getElementById("switch_"+screen).style.display = "block" ;
        CurrentHotScreen = screen ;
}
function refreshHotQuery(){
        refreshHotQueryTimer = null;
        setHotQueryList(CurrentHotScreen+1);
        refreshHotQueryTimer = setTimeout('refreshHotQuery();', 3000);
}
                       
function cleanallstyle() {
for (i=0;i<4;i++) {
                document.getElementById("focuss_"+i).className = "" ;
        }
}
function show_focuss_image(index) {
        clearTimeout(refreshHotQueryTimer);
        setHotQueryList(index);
        refreshHotQueryTimer = setTimeout('refreshHotQuery();', 3000);
}
function setClick() {
        clearTimeout(refreshHotQueryTimer);
}
var refreshHotQueryTimer = null ;
var hot_query_td =  document.getElementById('HotSearchList');
setHotQueryList(CurrentHotScreen);
refreshHotQueryTimer = setTimeout('refreshHotQuery();', 3000);