[javascript] Input mask for numeric and decimal

I realized a software application management invoicing after having tested my program I noticed the following error: my table in sqlserver contains: price numeric (6,2) the user of my program enter price as 555.00 is good. but when he put 555555 it's error, so I need to specify the mask where the mantissa is optional 0 to 999 and the decimal part is programmable 2 or 3 according to choice of the user, I'm using JQuery Masked input plugin and I have not found good regular expression, please, help, I'm working with jsp / servlet.

or also

<input type="text" onkeypress="handleNumber(event, '€ {-10,3} $')" placeholder="€  $" size=25>

with

function handleNumber(event, mask) {
    /* numeric mask with pre, post, minus sign, dots and comma as decimal separator
        {}: positive integer
        {10}: positive integer max 10 digit
        {,3}: positive float max 3 decimal
        {10,3}: positive float max 7 digit and 3 decimal
        {null,null}: positive integer
        {10,null}: positive integer max 10 digit
        {null,3}: positive float max 3 decimal
        {-}: positive or negative integer
        {-10}: positive or negative integer max 10 digit
        {-,3}: positive or negative float max 3 decimal
        {-10,3}: positive or negative float max 7 digit and 3 decimal
    */
    with (event) {
        stopPropagation()
        preventDefault()
        if (!charCode) return
        var c = String.fromCharCode(charCode)
        if (c.match(/[^-\d,]/)) return
        with (target) {
            var txt = value.substring(0, selectionStart) + c + value.substr(selectionEnd)
            var pos = selectionStart + 1
        }
    }
    var dot = count(txt, /\./, pos)
    txt = txt.replace(/[^-\d,]/g,'')

    var mask = mask.match(/^(\D*)\{(-)?(\d*|null)?(?:,(\d+|null))?\}(\D*)$/); if (!mask) return // meglio exception?
    var sign = !!mask[2], decimals = +mask[4], integers = Math.max(0, +mask[3] - (decimals || 0))
    if (!txt.match('^' + (!sign?'':'-?') + '\\d*' + (!decimals?'':'(,\\d*)?') + '$')) return

    txt = txt.split(',')
    if (integers && txt[0] && count(txt[0],/\d/) > integers) return
    if (decimals && txt[1] && txt[1].length > decimals) return
    txt[0] = txt[0].replace(/\B(?=(\d{3})+(?!\d))/g, '.')

    with (event.target) {
        value = mask[1] + txt.join(',') + mask[5]
        selectionStart = selectionEnd = pos + (pos==1 ? mask[1].length : count(value, /\./, pos) - dot) 
    }

    function count(str, c, e) {
        e = e || str.length
        for (var n=0, i=0; i<e; i+=1) if (str.charAt(i).match(c)) n+=1
        return n
    }
}

If your system is in English, use @Rick answer:

If your system is in Brazilian Portuguese, use this:

Import:

<script
        src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>

    <script     src="https://cdnjs.cloudflare.com/ajax/libs/jquery.mask/1.14.15/jquery.mask.min.js"></script>

    <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery.inputmask/3.2.6/jquery.inputmask.bundle.min.js"></script>

HTML:

<input class="mask" type="text" />

JS:

$(".mask").inputmask('Regex', {regex: "^[0-9]{1,6}(\\,\\d{1,2})?$"});

Its because in Brazilian Portuguese we write "1.000.000,00" and not "1,000,000.00" like in English, so if you use "." the system will not understand a decimal mark.

It is it, I hope that it help someone. I spend a lot of time to understand it.

Use tow function to solve it ,Very simple and useful:

HTML:

<input class="int-number" type="text" />
<input class="decimal-number" type="text" />

JQuery:

//Integer Number
$(document).on("input", ".int-number", function (e) {
  this.value = this.value.replace(/[^0-9]/g, '');
});

//Decimal Number
$(document).on("input", ".decimal-number", function (e) {
    this.value = this.value.replace(/[^0-9.]/g, '').replace(/(\..*)\./g, '$1');
});

Try imaskjs. It has Number, RegExp and other masks. Very simple to extend.

using jQuery input mask plugin (6 whole and 2 decimal places):

HTML:

<input class="mask" type="text" />

jQuery:

$(".mask").inputmask('Regex', {regex: "^[0-9]{1,6}(\\.\\d{1,2})?$"});

I hope this helps someone

You can do it using jquery inputmask plugin.

HTML:

<input id="price" type="text">

Javascript:

$('#price').inputmask({
  alias: 'numeric', 
  allowMinus: false,  
  digits: 2, 
  max: 999.99
});

https://codepen.io/vladimir-vovk/pen/BgNLgv

Now that I understand better what you need, here's what I propose. Add a keyup handler for your textbox that checks the textbox contents with this regex ^[0-9]{1,14}\.[0-9]{2}$ and if it doesn't match, make the background red or show a text or whatever you like. Here's the code to put in document.ready

$(document).ready(function() {
    $('selectorForTextbox').bind('keyup', function(e) {
        if (e.srcElement.value.match(/^[0-9]{1,14}\.[0-9]{2}$/) === null) {
            $(this).addClass('invalid');
        } else {
            $(this).removeClass('invalid');
        }
    });
});

Here's a JSFiddle of this in action. Also, do the same regex server side and if it doesn't match, the requirements have not been met. You can also do this check the onsubmit event and not let the user submit the page if the regex didn't match.

The reason for not enforcing the mask upon text inserting is that it complicates things a lot, e.g. as I mentioned in the comment, the user cannot begin entering the valid input since the beggining of it is not valid. It is possible though, but I suggest this instead.