編輯代碼:
查看結果 »
試一試 - ©
w3ii.com
<!DOCTYPE html> <html> <body> <form action="demo_form.asp" method="get"> Name: <input type="text" id="myInput" name="fname" required> <input type="submit" value="Submit"> </form> <p><strong>Note:</strong> The oninvalid event is not supported in Internet Explorer 9 and earlier or Safari.</p> <script> document.getElementById("myInput").oninvalid = function() {myFunction()}; function myFunction() { alert("You must fill out the form!"); } </script> </body> </html>