How to Restrict HTML Text Input to Numeric Values Only?

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)) {
                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")) {
                this.classList.add("input-error");
                this.setCustomValidity(errMsg);
                this.reportValidity();
                this.value = this.oldValue;
                this.setSelectionRange(this.oldSelectionStart, this.oldSelectionEnd);
            } else {
                this.value = "";
            }
        });
    });
}

setInputFilter(document.getElementById("myTextBox"), function (value) {
    return /^\d*\.?\d*$/.test(value); 
});