HTML5 Typography - Learn HTML5 by Creating Fun Games - page 77

• multiple (acceptable values include multiple , "" , or empty): Speci-
fies that multiple values are allowed in this element.
• readonly (acceptable values include readonly , "" , or empty): Speci-
fies that the value of this element cannot be changed by the user.
• required (acceptable values include required , "" , or empty): Speci-
fies that this element must have a valid value in order for the form to be
allowed to submit.
• value (value must be a valid e-mail address and must adhere to any
further restrictions specified by the pattern attribute, if any): Specifies the
actual e-mail address represented by this element or a comma-separated
list of valid e-mail addresses when the multiple attribute is present.

Note

For those not familiar with JavaScript's regular expression language, or who
need a refresher, following is a summary of the syntax:

[rodig] (brackets): used to match anything found within the brackets. For ex-
ample: match any one of the letters within the brackets.

[^rodig] (negative brackets): Used to match anything not found within the
brackets. For example, match any character except one of the letters within the
brackets.

[D-M] (range): Used to match a range of characters or numbers. For example,
match any characters between the capital letters D and M.

(me|you|us) (pipe): Used to match alternative options. For example, match
either of the words within the parenthesis.

. (period): Match any characters, expect for a new line character or a line termin-
ator character.

\w (word character): Match any letter, number, or an underscore.

\W (non-word character): Match any character that is not a word characters.