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>