Forms >>> Copy Name.
Allows the user to enter their name in the first field and have copies it to the second field for use as the User ID. It occurs instantly when they click the next field or the submit button. And, if the user tries to modify the second field, it is changed back to the value of the name field. Definitely a good example of the onChange() event handler in use.
Add the below code to the <body> section of your page: