JSFiddle - React, Tailwind, and code Playground

by Nofiden Noble

HTML

<span id="idtelf">123456789</span>

JavaScript

numberValidate("idtelf")
function numberValidate(idtelf){
    var input = document.getElementById('idtelf');

    var number = parseInt(input.value);
    var charactersLength = (""+number).length;
    if(isNaN(number) || charactersLength !=9  )
    {
        alert(  "Enter a valid number ");
    }
    else {
            alert(  "correct");
       }
};