<!DOCTYPE HTML>
<html>
<head>
    <meta charset="utf-8">
    <title>42度空间-身份证号码的正则表达式及验证详解-日期测试</title>
</head>
<body>
<div id="main"></div>
<script>
    console.log = function(val) {
        document.getElementById("main").innerHTML += val +"<br />";
    }
    var checkDate = function (val) {
        var pattern = /^(18|19|20)\d{2}((0[1-9])|(1[0-2]))(([0-2][1-9])|10|20|30|31)$/;
        if(pattern.test(val)) {
            var year = val.substring(0, 4);
            var month = val.substring(4, 6);
            var date = val.substring(6, 8);
            var date2 = new Date(year+"-"+month+"-"+date);
            if(date2 && date2.getMonth() == (parseInt(month) - 1)) {
                return true;
            }
        }
        return false;
    }
    //输出 true
    console.log(checkDate("20180212"));
    //输出 false 2月没有31日
    console.log(checkDate("20180231"));
</script>
</body>
</html>