JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" id="inputcpf" />
<button class="btnchec">verify</button>
JavaScript
function phonenumber(inputtxt) {
var phoneno = /^(\++(([0-9]{2}))|([0-9]{4}))[-\s\.]?[0-9]{4}[-\s\.]?[0-9]{4}/
if (inputtxt.match(phoneno)) {
alert("GOOD");
} else {
alert("PLease input correct number");
}
}
$(".btnchec").click(function () {
var inputtxt = $("#inputcpf").val();
console.log(phonenumber(inputtxt));
});