Given a string str
, how could I check if it is in the dd/mm/yyyy
format and contains a legal date ?
Some examples:
bla bla // false
14/09/2011 // true
09/14/2011 // false
14/9/2011 // false
1/09/2011 // false
14/09/11 // false
14.09.2011 // false
14/00/2011 // false
29/02/2011 // false
14/09/9999 // true
parseExact so you can just do Date. parseExact(dateString,"dd/MM/yyyy") .
The United States is one of the few countries that use “mm-dd-yyyy” as their date format–which is very very unique! The day is written first and the year last in most countries (dd-mm-yyyy) and some nations, such as Iran, Korea, and China, write the year first and the day last (yyyy-mm-dd).
DateValidator validator = new DateValidatorUsingDateFormat("MM/dd/yyyy"); assertTrue(validator. isValid("02/28/2019")); assertFalse(validator. isValid("02/30/2019"));
Edit: exact solution below
You could do something like this, but with a more accurate algorithm for day validation:
function testDate(str) {
var t = str.match(/^(\d{2})\/(\d{2})\/(\d{4})$/);
if(t === null)
return false;
var d = +t[1], m = +t[2], y = +t[3];
// Below should be a more acurate algorithm
if(m >= 1 && m <= 12 && d >= 1 && d <= 31) {
return true;
}
return false;
}
http://jsfiddle.net/aMWtj/
Date validation alg.: http://www.eee.hiflyers.co.uk/ProgPrac/DateValidation-algorithm.pdf
Exact solution: function that returns a parsed date or null, depending exactly on your requirements.
function parseDate(str) {
var t = str.match(/^(\d{2})\/(\d{2})\/(\d{4})$/);
if(t !== null){
var d = +t[1], m = +t[2], y = +t[3];
var date = new Date(y, m - 1, d);
if(date.getFullYear() === y && date.getMonth() === m - 1) {
return date;
}
}
return null;
}
http://jsfiddle.net/aMWtj/2/
In case you need the function to return true/false and for a yyyy/mm/dd format
function IsValidDate(pText) {
var isValid = false ;
var t = pText.match(/^(\d{4})\/(\d{2})\/(\d{2})$/);
if (t !== null) {
var y = +t[1], m = +t[2], d = +t[3];
var date = new Date(y, m - 1, d);
isValid = (date.getFullYear() === y && date.getMonth() === m - 1) ;
}
return isValid ;
}
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