JSFiddle - React, Tailwind, and code Playground

HTML

<form method="get">
    <div class="inputWrapper">
        <label for="name">Name</label>
        <input type="text" id="name" placeholder="Name" onChange="checkName(this)" >
    </div>
    <div class="inputWrapper">
        <label for="age">Age</label>
        <input type="number" id="age" placeholder="Age" min="0" max="150">
    </div>
    <div class="inputWrapper">
        <label for="location">Location</label>
        <input type="text" id="location" placeholder="Location">
    </div>
    <div class="inputWrapper">
        <button type="submit">Submit</button>
    </div>
</form>

CSS

.inputWrapper {
    margin: 10px 0;
}

label {
    display: block;
    font-weight: bold;
}

input {
    display: block;
}

JavaScript

function checkName(input) {

    // Check if input contains a digit
    if (/\d/.test(input.value)) {
        alert('Name contains a number');

        // Remove all digit characters
        input.value = input.value.replace(/\d/gi, '');
    }

    // Check if input is empty
    if (input.value === '') {
        alert('Name is empty');
    }

    return true;
}