In javascript how do I get date '02/27/2010' to pass but '02/31/2010' to fail?

Question

When I type in '02/27/2010' it is not a NaN. also when I type in '02/31/2010' it is also not a NaN when I use the Date and getDate("mydate") function. It will change this to March 3rd?

Is there a way to determine if the date is a real date without adding days to jump to the next month or year?

Thanks, Marc

score 2 · Accepted Answer · answered May 03 '11 at 22:26

This is one way:

  String.prototype.isValidDate = function(){
    var arrDate = this.split("/");
    if(arrDate.length!=3)return false;
    var month = parseInt(arrDate[0],10);
    var day = parseInt(arrDate[1],10);
    var year = parseInt(arrDate[2],10);                                  
    var dateComp = new Date(year, month-1, day);
    return (month == dateComp.getMonth()+1 &&
            day == dateComp.getDate() && 
            year == dateComp.getFullYear());
  };

  alert("2/1/2011".isValidDate());  
  alert("2/31/2011".isValidDate());
  alert("02/01/2011".isValidDate());

Example

score 1 · Answer 2 · answered May 03 '11 at 22:08

1

You may checkout datejs for everything that's dates manipulations in javascript.

answered May 03 '11 at 22:08

Darin Dimitrov

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@Rudie, sure, it all depends on what are the requirements. Sometimes 26KB are better than reinventing the wheel by writing some 2KB of crappy javascript code that works in 73% of the cases and breaks in the other 27% and that we need to maintain and that only the author and God are capable of. – Darin Dimitrov May 03 '11 at 22:14
Excellent point. It all depends on the case. I've saved the website to ma favs =) – Rudie May 03 '11 at 23:00

score 0 · Answer 3 · edited May 23 '17 at 11:43

0

Detecting an "invalid date" Date instance in JavaScript looks like that is the answer, from what I can tell.

edited May 23 '17 at 11:43

Community

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answered May 03 '11 at 22:09

Paul Zaczkowski

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That will just say if it is a valid date object, it will not verify that the date supplied is the same as the user entered. – epascarello May 03 '11 at 22:33

score 0 · Answer 4 · answered May 04 '11 at 02:47

//

function isvalid_mdy(s){
    var day, A= s.split(/\D+/).map(function(itm,i){return parseInt(itm,10)});
    A[0]-=1;
    try{
        day= new Date(A[2], A[0], A[1]);
        if(day.getMonth()== A[0] && day.getDate()== A[1]) return day;
        throw 'Bad Date ';
    }
    catch(er){
        return NaN;
    }
}
function isvalid_dmy(s){
    var day, A= s.split(/\D+/).map(function(itm,i){return parseInt(itm,10)});
    A[1]-=1;
    try{
        day= new Date(A[2], A[1], A[0]);
        if(day.getMonth()== A[1] && day.getDate()== A[0]) return day;
        throw 'Bad Date ';
    }
    catch(er){
        return NaN;
    }
}

In javascript how do I get date '02/27/2010' to pass but '02/31/2010' to fail?

4 Answers4