Regular Expression for MM/DD/YYYY in Javascript

Question

I've just written this regular expression in javaScript however it doesn't seem to work, here's my function:

function isGoodDate(dt){
    var reGoodDate = new RegExp("/^((0?[1-9]|1[012])[- /.](0?[1-9]|[12][0-9]|3[01])[- /.](19|20)?[0-9]{2})*$/");
    return reGoodDate.test(dt);
}

and this is how I call it in my form validation

if(!isGoodDate(userInput[1].value)){
           alert("date not in correct format of MM/dd/YYYY");
           return false;  
        }

now I want it to return MM/DD/YYYY however if I put a valid date in it raises the alert? Any ideas anyone?

Answer 1

Attention, before you copy+paste: The question contains some syntactic errors in its regex. This answer is correcting the syntax. It is not claiming to be the best regex for date/time parsing.

Try this:

function isGoodDate(dt){
    var reGoodDate = /^((0?[1-9]|1[012])[- /.](0?[1-9]|[12][0-9]|3[01])[- /.](19|20)?[0-9]{2})*$/;
    return reGoodDate.test(dt);
}

You either declare a regular expression with:

new RegExp("^((0?[1-9]|1[012])[- /.](0?[1-9]|[12][0-9]|3[01])[- /.](19|20)?[0-9]{2})*$")

Or:

/^((0?[1-9]|1[012])[- /.](0?[1-9]|[12][0-9]|3[01])[- /.](19|20)?[0-9]{2})*$/

Notice the /

Answer 2

Maybe because you are declaring the isGoodDate() function, and then you are calling the isCorrectDate() function?

Try:

function isGoodDate(dt){
    var reGoodDate = /^(?:(0[1-9]|1[012])[\/.](0[1-9]|[12][0-9]|3[01])[\/.](19|20)[0-9]{2})$/;
    return reGoodDate.test(dt);
}

Works like a charm, test it here .

Notice, this regex will validate dates from 01/01/1900 through 31/12/2099 . If you want to change the year boundaries, change these numbers (19|20) on the last regex block. Eg If you want the year ranges to be from 01/01/1800 through 31/12/2099 , just change it to (18|20) .

Answer 3

Add this in your code, it working perfectly fine it here. click here http://jsfiddle.net/Shef/5Sfq6/

function isGoodDate(dt){
var reGoodDate = /^(?:(0[1-9]|1[012])[\/.](0[1-9]|[12][0-9]|3[01])[\/.](19|20)[0-9]{2})$/;
return reGoodDate.test(dt);

}

Answer 4

I don't think you need a regular expression for this. Try this:

function isGoodDate(dt){
    var dts  = dt.split('/').reverse()
       ,dateTest = new Date(dts.join('/'));
    return isNaN(dateTest) ? false : true;
}

//explained
    var dts  = dt.split('/').reverse()
//      ^ split input and reverse the result
//        ('01/11/2010' becomes [2010,11,01]
//        this way you can make a 'universal' 
//        datestring out of it
       ,dateTest = new Date(dts.join('/'));
//     ^ try converting to a date from the 
//       array just produced, joined by '/'
    return isNaN(dateTest) ? false : true;
//         ^ if the date is invalid, it returns NaN
//           so, if that's the case, return false

Answer 5

I agree with @KooiInc, but it is not enough to test for NaN

function isGoodDate(dt){
    var dts  = dt.split('/').reverse()
       ,dateTest = new Date(dts.join('/'));
    return !isNaN(dateTest) && 
       dateTest.getFullYear()===parseInt(dts[0],10) &&
       dateTest.getMonth()===(parseInt(dts[1],10)-1) &&
       dateTest.getDate()===parseInt(dts[2],10) 
}

which will handle 29/2/2001 and 31/4/2011

---

For this script to handle US dates do

function isGoodDate(dt){
    var dts  = dt.split('/')
       ,dateTest = new Date(dt);
    return !isNaN(dateTest) && 
       dateTest.getFullYear()===parseInt(dts[2],10) &&
       dateTest.getMonth()===(parseInt(dts[0],10)-1) &&
       dateTest.getDate()===parseInt(dts[1],10) 
}

Answer 6

Validate (DD-MM-YYYY) format :)

function isGoodDate(dt) {
    var reGoodDate = /^(?:(0[1-9]|[12][0-9]|3[01])[\-.](0[1-9]|1[012])[\-.](19|20)[0-9]{2})$/;
    return reGoodDate.test(dt);
}

Answer 7

Try the below code which accepts following date formats:

MM-DD-YYYY, MM-DD-YY, DD-MM-YYYY, DD-MM-YY, MM/DD/YYYY, MM/DD/YY, DD/MM/YYYY, DD/MM/YY, MM\\DD\\YYYY, MM\\DD\\YY, DD\\MM\\YYYY, DD\\MM\\YY

function isGoodDate(dt) {
    var reGoodDate = /(?:((0\d|[12]\d|3[01])|(0\d|1[012]))[\-|\\|\/]((0\d|1[012])|(0\d|[12]\d|3[01]))[\-|\\|\/](((19|20)\d{2})|\d\d))/;
    return reGoodDate.test(dt);
}

Answer 8

(/^(0[1-9]|1[012])- /.- /.\\d\\d$/) 你可以使用这个肯定会工作，这适用于 MM/DD/YYYY