Dealing with currency in Javascript

Question

I was wondering is this ideal solution to deal with currency in Javascript? Idea is to limit user that he can only write numbers and decimal point in input. This code is mix of answers I found on this site and some of my own.

HTML:

<p><input type="text" class="form-control" id="cijenanovogtroska" onkeypress="return isNumberKey(event)" name="txtChar"></p>

JS File:

function isNumberKey(evt)
   {
     var charCode = (evt.which) ? evt.which : evt.keyCode;
     if (charCode == 46) // checks if you press dot on keyboard
     {
       if ($("#cijenanovogtroska:text").val().includes(".")) // that text wont include first dot, but you will limit every other try
       {
        return false;
       }
       if ($("#cijenanovogtroska:text").val() == "") // It checks if this string is empty, so dot cant go on first place
       {
        return false;
       }
     }
     if (charCode != 46 && charCode > 31 && (charCode < 48 || charCode > 57)) // numbers and dots are possible inputs
     {
        return false;
      }
    else
     {
     return true;
     }
}

Addition to this function, in function where you have to do stuff (etc. save data to database) You would have to check that "." is not on last position.

Is there any better implementation to do it than this?:

  if (cijena.slice(-1) != ".")
  {
    //do stuff
  }
  else
  {
    alert("You have decimal point on last place!");
  }

score 1 · Accepted Answer · answered Jan 16 '21 at 17:07

1

Why not a regex ?

<input type=“text” pattern=“^\$?([0-9]{1,3},([0-9]{3},)*[0-9]{3}|[0-9]+)(.[0-9][0-9])?$” />

PS: i just copy pasted the first regex I found if that one does not fill yow needs go to google a look for regex currency

answered Jan 16 '21 at 17:07

Ernesto

3,944
1
14
29

Thanks, I found regex for my needs [here](https://stackoverflow.com/questions/5963158/html5-form-input-pattern-currency-format) – nniks19 Jan 16 '21 at 17:14

score 1 · Answer 2 · answered Jan 16 '21 at 17:34

1

You could alternatively also use HTML5 validation, see here

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<form>
<input type="text" name="txtChar" pattern="[\d]+([.,][\d]{0,2})?" 
       placeholder="number with max. 2 digits"
       title="enter a valid currency amount #[,.]##" required><br/>
</form>

Simply enter a few test values and press return.

answered Jan 16 '21 at 17:34

Carsten Massmann

26,510
2
22
43

I just tried this on code snippet, but it allows me to write text – nniks19 Jan 16 '21 at 17:54
It does, but it will refuse to submit the form (press `´), as long as the contents does not comply with the given pattern. Try it out. – Carsten Massmann Jan 16 '21 at 18:14

score 0 · Answer 3 · answered Jan 16 '21 at 17:15

0

you can easily specify it in the input tag to take type numbers and it will do the same of all this functions like so :-

<input type='number' name='cijenanovogtroska' id='txtChar'>

answered Jan 16 '21 at 17:15

Mohamed Ghoneim

153
6

This works, but user can edit input field and put dots or format I dont want there. I want that to be limited so there are no mistakes in input. – nniks19 Jan 16 '21 at 17:16
if you want to save it to a database , you can specify it as number in the database . so if the user input any thing but numbers it will return error and then you can handle the error message' – Mohamed Ghoneim Jan 16 '21 at 17:19
I am using Google Firebase and it will just throw error without warning the user that input is not like it should be. – nniks19 Jan 16 '21 at 17:20
i didn`t use firebase before ,so good luck – Mohamed Ghoneim Jan 16 '21 at 17:22

Dealing with currency in Javascript

3 Answers3