Как в маске телефона увеличить кол-во знаков?

Question

[Junior Coder]

Сделать более 20 или выставить точное значение?!

window.addEventListener("DOMContentLoaded", function() {
    [].forEach.call( document.querySelectorAll('.tel'), function(input) {
    var keyCode;
    function mask(event) {
        event.keyCode && (keyCode = event.keyCode);
        var pos = this.selectionStart;
        if (pos < 3) event.preventDefault();
        var matrix = "+7 (___) ___ ____",
            i = 0,
            def = matrix.replace(/\D/g, ""),
            val = this.value.replace(/\D/g, ""),
            new_value = matrix.replace(/[_\d]/g, function(a) {
                return i < val.length ? val.charAt(i++) || def.charAt(i) : a
            });
        i = new_value.indexOf("_");
        if (i != -1) {
            i < 5 && (i = 3);
            new_value = new_value.slice(0, i)
        }
        var reg = matrix.substr(0, this.value.length).replace(/_+/g,
            function(a) {
                return "\\d{1," + a.length + "}"
            }).replace(/[+()]/g, "\\$&");
        reg = new RegExp("^" + reg + "$");
        if (!reg.test(this.value) || this.value.length < 5 || keyCode > 47 && keyCode < 58) this.value = new_value;
        if (event.type == "blur" && this.value.length < 5)  this.value = ""
    }

    input.addEventListener("input", mask, false);
    input.addEventListener("focus", mask, false);
    input.addEventListener("blur", mask, false);
    input.addEventListener("keydown", mask, false)

  });

});

Answer 1

[Taulan Khatuaev]

window.addEventListener("DOMContentLoaded", function() {
  [].forEach.call(document.querySelectorAll('.tel'), function(input) {
    var keyCode;
    function mask(event) {
      event.keyCode && (keyCode = event.keyCode);
      var pos = this.selectionStart;
      if (pos < 3) event.preventDefault();
      var matrix = "+7 (____) ____-___",
          i = 0,
          def = matrix.replace(/\D/g, ""),
          val = this.value.replace(/\D/g, ""),
          new_value = matrix.replace(/[_\d]/g, function(a) {
            return i < val.length ? val.charAt(i++) || def.charAt(i) : a;
          });
      i = new_value.indexOf("_");
      if (i != -1) {
        i < 5 && (i = 3);
        new_value = new_value.slice(0, i);
      }
      var reg = matrix
        .substr(0, this.value.length)
        .replace(/_+/g, function(a) {
          return "\\d{1," + a.length + "}";
        })
        .replace(/[+()]/g, "\\$&");
      reg = new RegExp("^" + reg + "$");
      if (!reg.test(this.value) || this.value.length < 5 || (keyCode > 47 && keyCode < 58))
        this.value = new_value;
      if (event.type == "blur" && this.value.length < 5) this.value = "";
    }

    input.addEventListener("input", mask, false);
    input.addEventListener("focus", mask, false);
    input.addEventListener("blur", mask, false);
    input.addEventListener("keydown", mask, false);
  });
});