JSFiddle - React, Tailwind, and code Playground

HTML

<html>
  <head></head>
  <body>
    
    <form name="myForm" onsubmit="return validateForm()" method="post">
    <input id = "name" type = "text" value="test">
      
     <button type="submit">submit</button> 
</form>
    
    
  </body>
</html>

<script src="https://code.jquery.com/jquery-3.6.0.js" integrity="sha256-H+K7U5CnXl1h5ywQfKtSj8PCmoN9aaq30gDh27Xc0jk=" crossorigin="anonymous"></script>

JavaScript

$(function(){

})

function validateForm(){
	var len = $('#name').val().length;

	if(len <= 0){

		return false;  
  }
  else{
		return true; 
  }
}