Sams Teach Yourself HTML, CSS & JavaScript Web Publishing in One Hour a Day

ptg16476052

322 LESSON 12: Designing Forms

The general rule when it comes to choosing between post and get is that if the form will

change any data on the server, you should use post. If the form is used to retrieve infor-

mation, using get is fine. For example, suppose that you’re writing a message board pro-

gram. The registration form for new users and the form used to publish messages should

use the post method. If you have a form that enables the user to show all the posts

entered on a certain date, it could use the get method.

HTML5 and modern browsers now offer a validation feature before the form is submit-

ted. The browsers use a combination of rules written in the control attributes and the

attribute types themselves to determine whether the content is what you’re asking for.

You’ll learn about this in more detail later in this lesson. But because of this feature, the

form tag has an attribute novalidate that lets you turn off validation on your forms. The

main reason you will use this attribute is to test the JavaScript and server-side validation

mechanisms you have in place. This is a Boolean attribute, so you don’t need to include

any values. Simply add it to your form tag:

<form novalidate>

Another new attribute of the <form> tag is the autocomplete attribute. It can have the

value of on or off. on is the default, and it tells the browser to attempt to predict the

value when a user is typing in a form control. By turning the autocomplete attribute off

you tell the browser to avoid suggesting values for form fields. You can turn autocomple-

tion on or off for your entire form by adding it to your <form> tag:

<form autocomplete="off">

Two other less-often used attributes of the <form> tag are enctype and accept-charset.

enctype defines how form data is encoded when it’s sent to the server, and accept-charset

defines the character encodings to be used for the form submission. The default for enctype

is application/x-www-form-urlencoded, and the default for accept-charset is the same

DO use the POST method when data

on the server will be changed in any

way.

DO use the GET method if the form

just requests data (like search forms,

for example).

DO use the GET method if you want to

bookmark the results of the form sub-

mission.

DON’T use the GET method if you do

not want the form parameters to be

visible in a URL.

DON’T use the GET method if the form

is used to delete information.

DO DON’T

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