JSFiddle - React, Tailwind, and code Playground

HTML

<input id="email" type="text" style="width:140px" name="email" value="enter e-mail"/>

JavaScript

var emailfield = document.getElementById('email');
 emailfield.onfocus = function(){
  if (this.value == 'enter e-mail') this.value = '';
 }
 emailfield.onblur= function(){
  if (this.value == '') this.value = 'enter e-mail';
 }