function topen(){ 
    document.getElementById("sc_nav").className="displayblock"; 
    } 
  function navArray(num,url) { 
    var navArray=document.getElementById("sc_nav").getElementsByTagName("li"); 
    var objChecked = document.getElementsByName ("checked"); 
    for(var i=0;i<navArray.length;i++){ 
        if(num == i ){ 
            navArray[num].className = "checked"; 
            document.getElementById("newsType").innerHTML=navArray[num].innerHTML; //将选择值赋值给隐藏表单 
            document.getElementById("sc_nav").className="displaynone"; 
        }else{         
            navArray[i].className = ""; 
        } 
    } 
    window.location.href= url;
}