HTML テキスト入力を数値のみを受け入れるように制限するにはどうすればよいですか?

function setInputFilter(textbox, inputFilter, errMsg) {
  [
    "input",
    "keydown",
    "keyup",
    "mousedown",
    "mouseup",
    "select",
    "contextmenu",
    "drop",
    "focusout",
  ].forEach(function (event) {
    textbox.addEventListener(event, function (e) {
      if (inputFilter(this.value)) {
        // Accepted value
        if ([
          "keydown",
          "mousedown",
          "focusout",
        ].indexOf(e.type) >= 0) {
          this.classList.remove("input-error");
          this.setCustomValidity("");
        }
        this.oldValue = this.value;
        this.oldSelectionStart = this.selectionStart;
        this.oldSelectionEnd = this.selectionEnd;
      } else if (this.hasOwnProperty("oldValue")) {
        // Rejected value: restore the previous one
        this.classList.add("input-error");
        this.setCustomValidity(errMsg);
        this.reportValidity();
        this.value = this.oldValue;
        this.setSelectionRange(this.oldSelectionStart, this.oldSelectionEnd);
      } else {
        // Rejected value: nothing to restore
        this.value = "";
      }
    });
  });
}

setInputFilter(document.getElementById("numericInput"), function (value) {
  return /^\d*\.?\d*$/.test(value); // Allow digits and '.' only
}, "Only numbers and '.' allowed");