下面代码中if语句，如果加入else后，所设置的if语句无法正常运行的原因是什么？

Question

例如下面代码：<script type="text/javascript">      window.onload= function w(){          function e(i){              if(i<10){                  i="0"+i;              }else{                  return i;}              }                    var time=new Date();          var year=time.getFullYear();          var month=time.getMonth()+1;          var day=time.getDate();          var week=time.getDay()          var weekday=new Array();            weekday[0]="星期日";            weekday[1]="星期一";            weekday[2]="星期二";            weekday[3]="星期三";            weekday[4]="星期四";            weekday[5]="星期五";            weekday[6]="星期六";          var h=time.getHours();          var m=time.getMinutes();                   var s=time.getSeconds();           m=e(m);           s=e(s);        document.getElementById("first1").innerHTML=year+"年"+month+"月"+day+"日"+weekday[week]+h+":"+m+":"+s;           setTimeout(w,500)        }                 </script>

Answer 1

if里面也需要return

if(i<10){
    i="0"+i;
    return i;
}else{
    return i;}
}