js判断是否为数字

function IsNum(num){
  var reNum=/^\d*$/;
  return(reNum.test(num));
}

var str=document.getElementById("name").value;
var reg = /^[\u4e00-\u9fa5]+$/i; //判断是否为汉字
if (!reg.test(str))
{
alert("请输入中文名字！");
document.form1.name.focus();
return false;
}
return true;

//判断是否为时间

function isDate(dateStr)
{
    var datePat = /^(\d{4})(\-)(\d{1,2})(\-)(\d{1,2})$/;
    var matchArray = dateStr.match(datePat);
    if (matchArray == null) return false;
    var month = matchArray[3];
    var day = matchArray[5];
    var year = matchArray[1];
    if (month < 1 || month > 12) return false;
    if (day < 1 || day > 31) return false;
    if ((month==4 || month==6 || month==9 || month==11) && day==31) return false;
    if (month == 2)
    {
        var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
        if (day > 29 || (day==29 && !isleap)) return false;
    }
    return true;
}