如何使用 JavaScript 更改输入中的特定值

Question

I have an input containing a date value

example:

<input type="text" name="cel_dafa" value="26/12/2018">

I want a button when pressed it increases the value one month

So that the result after the pressure:

<input type="text" name="cel_dafa" value="26/1/2019">

Note: I do not want to harm the day, Only the month and year if at the end of the year

Answer 1

Ok, so consider you have a button like;

<button onclick="increase()"> Click Me </button>

And input like;

<input type="text" id="date" name="cel_dafa" value="26/12/2018">

Now code of increase function;

 function increase()
 {
     var currentDate = document.getElementById('date').value;
     var parts = currentDate.split("/");
     var day = parts[0];
     var month = parts[1];
     var year = parts[2];

     var d = new Date(year, month - 1, day); 
     d.setMonth(d.getMonth() + 1);
     var newDate = d.getDate() + "/" + (d.getMonth() + 1) + "/" + d.getFullYear();
     document.getElementById('date').value = newDate;
 }

Answer 2

Html

<input type="text" id="date-input" name="cel_dafa" value="26/12/2018">

<button onclick="increaseDate()">submit</button>

JS

 function increaseDate() {  
    var dateInput = document.querySelector('#date-input').value;    
    var day = dateInput.split('/')[0];
    var month = dateInput.split('/')[1];
    var year = dateInput.split('/')[2];    
    if (month > 11) {
        year = parseInt(year) + 1;
        month = 1
    } else {
        month = parseInt(month) + 1;
    }
    var newDate = day +"/"+ month +"/"+ year;   
    document.querySelector('#date-input').value = newDate;
}