js 判断是否是时间

Question

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;
}

帮忙解释一下
var datePat = /^(\d{4})(\-)(\d{1,2})(\-)(\d{1,2})$/;

Answer 1

/^(\d{4})(\-)(\d{1,2})(\-)(\d{1,2})$/;

正则表达式，你可以找找这方面的资料
大概说说吧

/^：行首
$/：行尾
(\d{4})：正好匹配4个数字（应该是代表年）
(\-)：中间有一杠
(\d{1,2})：1位到2位的数字（应该代表月）
(\-)：还是一杠
(\d{1,2})：还是代表1到2位的数字（代表日期）

Answer 2

<script language="JavaScript"><!--
function validateDate(date) {
// NaN is never equal to itself.
if (Date.parse(date) != Date.parse(date))
document.write(date + ' - Invalid date<br>');
else
document.write(date + ' - Valid date<br>');
}

validateDate('hello world');
validateDate('29 January 1999');
validateDate('February 30 2000');
validateDate('Sat 8 2000 Jan');
//--></script>

Answer 3

日期