通过出生年月计算年龄(JS)

<script   language=javascript>   
  function   ages(str)   
  {   
        var   r   =   str.match(/^(\d{1,4})(-|\/)(\d{1,2})\2(\d{1,2})$/);     
        if(r==null)return   false;     
        var   d=   new   Date(r[1],   r[3]-1,   r[4]);     
        if   (d.getFullYear()==r[1]&&(d.getMonth()+1)==r[3]&&d.getDate()==r[4])   
        {   
              var   Y   =   new   Date().getFullYear();   
              return("年龄   =   "+   (Y-r[1])   +"   周岁");   
        }   
        return("输入的日期格式错误！");   
  }   
  alert(ages("1980-03-22"));   
  alert(ages("2002-01-31"));   
  alert(ages("2002-01-41"));   
  </script>