JSFiddle - React, Tailwind, and code Playground

HTML

<input id='webcallbackinput' onkeyup='checkParams()' />
<input type='button' id='callme' value='call me' disabled>

JavaScript

function checkParams() {
    var phone = $('#webcallbackinput').val();
    
    if(phone.length >= 11) {
        $('#callme').removeAttr('disabled');
    } else {
        $('#callme').attr('disabled', 'disabled');
    }
}