如何使用格式“mm / dd / yyyy”验证日期在JavaScript? [英] How to validate date with format "mm/dd/yyyy" in JavaScript?
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问题描述
我想使用格式 mm / dd / yyyy
在输入上验证日期格式。
I want to validate the date format on an input using the format mm/dd/yyyy
.
我发现以下代码在一个网站,然后使用它,但它不起作用:
I found below codes in one site and then used it but it doesn't work:
function isDate(ExpiryDate) {
var objDate, // date object initialized from the ExpiryDate string
mSeconds, // ExpiryDate in milliseconds
day, // day
month, // month
year; // year
// date length should be 10 characters (no more no less)
if (ExpiryDate.length !== 10) {
return false;
}
// third and sixth character should be '/'
if (ExpiryDate.substring(2, 3) !== '/' || ExpiryDate.substring(5, 6) !== '/') {
return false;
}
// extract month, day and year from the ExpiryDate (expected format is mm/dd/yyyy)
// subtraction will cast variables to integer implicitly (needed
// for !== comparing)
month = ExpiryDate.substring(0, 2) - 1; // because months in JS start from 0
day = ExpiryDate.substring(3, 5) - 0;
year = ExpiryDate.substring(6, 10) - 0;
// test year range
if (year < 1000 || year > 3000) {
return false;
}
// convert ExpiryDate to milliseconds
mSeconds = (new Date(year, month, day)).getTime();
// initialize Date() object from calculated milliseconds
objDate = new Date();
objDate.setTime(mSeconds);
// compare input date and parts from Date() object
// if difference exists then date isn't valid
if (objDate.getFullYear() !== year ||
objDate.getMonth() !== month ||
objDate.getDate() !== day) {
return false;
}
// otherwise return true
return true;
}
function checkDate(){
// define date string to test
var ExpiryDate = document.getElementById(' ExpiryDate').value;
// check date and print message
if (isDate(ExpiryDate)) {
alert('OK');
}
else {
alert('Invalid date format!');
}
}
有什么可能出错的建议? >
Any suggestion about what could be wrong?
推荐答案
我想Niklas对你的问题有正确的答案。此外,我认为以下日期验证功能有点简单:
I think Niklas has the right answer to your problem. Besides that, I think the following date validation function is a little bit easier to read:
// Validates that the input string is a valid date formatted as "mm/dd/yyyy"
function isValidDate(dateString)
{
// First check for the pattern
if(!/^\d{1,2}\/\d{1,2}\/\d{4}$/.test(dateString))
return false;
// Parse the date parts to integers
var parts = dateString.split("/");
var day = parseInt(parts[1], 10);
var month = parseInt(parts[0], 10);
var year = parseInt(parts[2], 10);
// Check the ranges of month and year
if(year < 1000 || year > 3000 || month == 0 || month > 12)
return false;
var monthLength = [ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ];
// Adjust for leap years
if(year % 400 == 0 || (year % 100 != 0 && year % 4 == 0))
monthLength[1] = 29;
// Check the range of the day
return day > 0 && day <= monthLength[month - 1];
};
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