<script language="javascript">
function checkWeekno()
{
    var weekno = document.forms[0].weekno;
    var num = weekno.value;
    if (trim(num)=="")
    {
        alert("请输入数据!");
        weekno.focus(); 
        return false;
    }
    if(isNaN(num))
    {
        alert("输入数据不合法,请输入整数!");
        weekno.focus();
        return false;
    }
    if(/^(\-?)(\d+)$/.test(num))
    {
        return true;
    }else{
        alert("输入数据不合法,请输入整数!");
        weekno.focus();
        return false;
    }
}         </script>