[adijadhav]

Hiii
in a form i am taking number of months then he enters first date. then next date must be automatically calculated.
like if 11 month and first date is 2017-24-03 then next date must be 2018-23-02. it must check leap year also

[amosbatto]

There are examples in the Datetime wiki page if you want to do this with PHP. If you want to do this with JavaScript, it is a bit harder.

For example you have two datetime fields with the IDs "contractStart" and "contractEnd". Then you can use the following JavaScript code, which automatically inserts the date 11 months later in the contractEnd when the value of contractStart changes:

Code: Select all

$("#contractStart").setOnchange( function(newVal, oldVal) {
  if (newVal == '') {
    $("#contractEnd").setValue('');
  }
  else {
    var contractStart = moment(newVal);
    var contractEnd = moment(contractStart).add(11, 'M');
    var contractMonthEnd = moment(contractEnd).endOf('month');
    //check whether the end month has fewer days in it than the start month:
    if (contractEnd.format("YYYY-MM-DD") > contractMonthEnd.format("YYYY-MM-DD")) {
       contractEnd = contractMonthEnd;
    }

    $("#contractEnd").setValue(contractEnd.format("YYYY-MM-DD"));
  }
})

Here is a sample DynaForm with this example:

test Momentjs.json

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