use html validation code example
Example: html form validation
<form action="">
<label for="name">Username</label>
<input id="name" type="text" required />
<label for="Email">Email</label>
<!-- The required attribute will prompt the user to make sure -->
<!-- the fields are not empty, and that the email is formatted correctly -->
<!-- if you want to use custom validation you should use regex in JavaScript -->
<input id="Email" type="text" required />
</form>