Keyup allow it to contain only one dot between input characters

Question

Personal how to allow it to contain only one point (.) between the characters typed in the input by checking with the jquery keyup event.

Example of an exit:

000.000000
1.000
99.9.99.999 // <- error não pode ter mais de 1 ponto

Code:

$('input').keyup(function(e){
  $(this).val(function() {
    var val = this.value;
    return val.replace(/(\.)+/g, function(char, str) {
      return str;
    });
  });
});

JSFIDDLE

Answer 1

I created a function called validaPontos() that will return the amount of dots that are in the field. after this compare only if it is greater than or equal to two and remove the character.

Example:

$('input').keyup(function(e) {
  var valor = this.value;
  var pattern = /\.(?=[^.]*$)/;
  if (validaPontos(valor) >= 2) {
    this.value = valor.replace(pattern, "");
  }
});

function validaPontos(valor) {
  var quantidadeDePontos = 0;
  for (var i = 0; i < valor.length; i++) {
    if (valor[i] === '.') {
      quantidadeDePontos++;
    }
  }
  return quantidadeDePontos;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
<input type="text" />

Updated If the user tries to type a dot in the middle the last point of the string will be removed!

Or you can also use a plugin for these validations: Maskmoney

Example of Use:

$('#currency').maskMoney();

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery-maskmoney/3.0.2/jquery.maskMoney.min.js"></script>


<input type="text" id="currency" />

Answer 2

Well... it gave me a certain job, but I think I finally got something quite interesting. Look:

With the existence of a point, if you try to add another after this you will not be able, for that the point should be deleted. Instead of the onKey, I used the onInput, which will detect if something is changed, with this the user can "browse" enters the reading without being played to the end of the input, beyond the question of performance, in which case the exclusion of the.

$('input').on("input", function(){
  var val = this.value;
  var test = /^[^.]?.[^.]*$/;
  if(test.test(val)){
    return;
  }else{
    var n = val.search(/\./);
    var beforeDot = val.substring(0, n);
    var dot = val.substring(n, n+1);
    var afterDot = val.substring(n+1, val.length);
    $(this).val(beforeDot.replace(/\./g, "") + dot + afterDot.replace(/\./g, ""));
}
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<input type="text" />

Answer 3

I got a more "compact" mode similar to @Gabrielrodrigues

$('input').keyup(function(e) {
  $(this).val(function() {
    var val = this.value;
    if (val.split('.').length > 2) val = val.replace(/\.+$/, '');
    return val;
  });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
<input type="text" />