编辑代码:
查看结果 »
试一试 - ©
w3ii.com
<!DOCTYPE html> <html> <body> <form action="demo_form.asp" method="post"> <input type="text" name="fname" required> <input type="submit" value="Submit"> </form> <p>If you click submit, without filling out the text field, your browser will display an error message.</p> </body> </html>