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<html><head><script>function validateForm() { let x = document.forms["myForm"]["fname"].value; if (x == "") { alert("Name must be filled out"); return false; }}</script></head><body><h2>JavaScript Validation</h2><form name="myForm" action="https://www.w3schools.com/action_page.php" onsubmit="return validateForm()" method="post"> Name: <input type="text" name="fname"> <input type="submit" value="Submit"></form></body><!-- Mirrored from www.w3schools.com/js/tryit.asp?filename=tryjs_validation_js by HTTrack Website Copier/3.x [XR&CO'2014], Wed, 21 Dec 2022 17:06:56 GMT --></html>