How to add form validation for empty input fields with JavaScript?

Javascript Web Development Object Oriented Programming

To add form validation for empty input fields with JavaScript, the code is as follows −

Example

<!DOCTYPE html>
<html>
<head></head>
<h1>JavaScript empty input field validation example</h1>
<form
name="Form1"
onsubmit="return emptyValidation()"
required>
Name: <input type="text" name="firstName" />
<input type="submit" value="Submit" />
</form>
<h2>Submit the form empty to see the validation performed</h2>
<script>
   function emptyValidation() {
      var formField = document.forms["Form1"]["firstName"].value;
      if (formField == "" || x == null) {
         alert("Name must be filled out");
         return false;
      }
   }
</script>
</body>
</html>