js正则验证日期（包括闰年）

function CheckObjDate(word)
{
    var checkResult = CheckDate(word);
    switch(checkResult)
    {
        case 'ERRORNODATE':
            alert('不能为空！');
            break;
        case 'ERRORDATEFORMAT':
            alert('时间格式不正确！');
            break;
        default:
            alert('通过！');
            return true;
    }

}
function CheckDate(checkDate)
{
     var reg =/^(?:(?:(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00)))(\/|-)(?:0?2\1(?:29)))|(?:(?:(?:1[6-9]|[2-9]\d)?\d{2})(\/|-)(?:(?:(?:0?[13578]|1[02])\2(?:31))|(?:(?:0?[1,3-9]|1[0-2])\2(29|30))|(?:(?:0?[1-9])|(?:1[0-2]))\2(?:0?[1-9]|1\d|2[0-8]))))$/;
    var word = checkDate;
    if(word.length == 0)
    {
        return 'ERRORNODATE';
    }
    var splitedWord = word.split("-");
    if(splitedWord.length > 3 || splitedWord.length < 2)
    {
        return 'ERRORDATEFORMAT';
    }
    else
    {
        for(var i = 0; i < splitedWord.length; i++)
            if(splitedWord[i].length == 0)
                return 'ERRORDATEFORMAT';
    }
    if(splitedWord.length == 2)
    {
        if(splitedWord[0].length < 1 || splitedWord[0].length > 2)
            return 'ERRORDATEFORMAT';
        else if(splitedWord[0].length == 1)
        {
           splitedWord[0] = "0" +  splitedWord[0];
        }
        if(splitedWord[1].length < 1 || splitedWord[1].length > 2)
            return 'ERRORDATEFORMAT';
        else if(splitedWord[1].length == 1)
        {
           splitedWord[1] = "0" +  splitedWord[1];
        }
        var now = new Date();
        word = now.getFullYear() + "/" + splitedWord[0] + "/" + splitedWord[1];
    }
    if(splitedWord.length == 3)
    {
        if(splitedWord[0].length < 1 || splitedWord[0].length > 4)
            return 'ERRORDATEFORMAT';
        else if(splitedWord[0].length == 1)
        {
           splitedWord[0] = "200" +  splitedWord[0];
        }
        else if(splitedWord[0].length == 2)
        {
           splitedWord[0] = "20" +  splitedWord[0];
        }
        if(splitedWord[1].length < 1 || splitedWord[1].length > 2)
            return 'ERRORDATEFORMAT';
        else if(splitedWord[1].length == 1)
        {
           splitedWord[1] = "0" +  splitedWord[1];
        }
        if(splitedWord[2].length < 1 || splitedWord[2].length > 2)
           return 'ERRORDATEFORMAT';
        else if(splitedWord[2].length == 1)
        {
           splitedWord[2] = "0" +  splitedWord[2];
        }
        word = splitedWord[0] + "/" + splitedWord[1] + "/" + splitedWord[2];
    }
    if(!(word.match(reg)))
    {
        return 'ERRORDATEFORMAT';
    }
    else
    {
        return word;
    }
}