Problem when compare 2 dates in javascript

Question

i have 1 problem, i wanna compare two dates between date born and today, the condition is date born must be less than today date, it worked at first, but if i pick another date from datepicker which is less than today, its still pop up alert. And it not ok. Anyone know why this this happened?

    function submitForm() {
        
        var dateborn = document.getElementById('dateborn').value;   
        var today = document.getElementById('today').value;
        
        if(dateborn != '')
        {           
            if(dateborn > today)
            {
            swal("Oops", "Date born must less than date today", "error");       
            return false;
            }
        }

            
    }

.value returns a string. You're comparing two strings, and not two dates. — Rickard Elimää
– Rickard Elimää, Commented Aug 9, 2021 at 6:10
1) developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… 2) stackoverflow.com/questions/492994/… — Aval Sarri
– Aval Sarri, Commented Aug 9, 2021 at 6:13
Since I guess you will now need to know how to properly compare them, convert the string into a date like this and compare afterwards. — bluejambo
– bluejambo, Commented Aug 9, 2021 at 6:13

Adem yalçın · Accepted Answer · 2021-08-09 06:14:39Z

1

If I were you I can use the timestamp to compare 2 dates.

function submitForm() {
        
        var dateborn = document.getElementById('dateborn').value;   
        var today = document.getElementById('today').value;
        const time1 = new Date(dateborn).getTime();
        const time2 = new Date(today).getTime(); // or new Date().getTime();
        if(dateborn != '')
        {           
            if(time1 > time2)
            {
            swal("Oops", "Date born must less than date today", "error");       
            return false;
            }
        }

answered Aug 9, 2021 at 6:14

Adem yalçın

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Comments

Muhammad Nizar · Accepted Answer · 2021-08-09 06:20:35Z

0

Try this

function submitForm() {
    
    var dateborn = document.getElementById('dateborn').value;   
    var today = document.getElementById('today').value;
    
    if(dateborn != '')
    {           
        if(Date(dateborn).getTime() > Date(today).getTime())
        {
        swal("Oops", "Date born must less than date today", "error");       
        return false;
        }
    }

        
}

answered Aug 9, 2021 at 6:20

Muhammad Nizar

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1 Comment

confused_cat Over a year ago

thanks for the solution, really appreciate it

Jesper · Accepted Answer · 2021-08-09 06:38:47Z

0

As for your question why this happened. i think your date picker does not give the date in ISO format. if your value is formatted like: YYYY-MM-DD (from biggest to smallest) you can compare it as a string. You can see this from this fiddle i made: JSfiddle

Does your date picker look like this:

<input type="date" id="d2" onChange="change(this)"/>

answered Aug 9, 2021 at 6:38

Jesper

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2 Comments

confused_cat Over a year ago

thanks for the solution, really appreciate it, Well btw i just only have 1 date picker which is the dateborn, while today value i get it from hidden input.

Jesper Over a year ago

@confused_cat If today is truly only for getting the current date.. Why not get it from javascript with new Date()?

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