JavaScript: The Definitive Guide, Fourth Edition

Name

escape( ) — encode a string

Availability

JavaScript 1.0; JScript 1.0; ECMAScript v1; deprecated in ECMAScript v3

Synopsis

escape(s)

Arguments

s

The string that is to be “escaped” or encoded.

Returns

An encoded copy of s in which certain characters have been replaced by hexadecimal escape sequences.

Description

escape( ) is a global function. It returns a new string that contains an encoded version of s. The string s itself is not modified.

escape( ) returns a string in which all characters of s other than ASCII letters, digits, and the punctuation characters @, *, _, +, -, ., and / have been replaced by escape sequences of the form % xx or %u xxxx (where x represents a hexadecimal digit). Unicode characters \u0000 to \u00ff are replaced with the % xx escape sequence, and all other Unicode characters are replaced with the %u xxxx sequence.

Use the unescape( ) function to decode a string encoded with escape( ).

In client-side JavaScript, a common use of escape( ) is to encode cookie values, which have restrictions on the punctuation characters they may contain. See the Document.cookie reference page in the client-side reference section.

Although the escape( ) function was standardized in the first version of ECMAScript, it has been deprecated and removed from the standard by ECMAScript v3. Implementations of ECMAScript are likely to implement this function, but they are not required to. In JavaScript 1.5 and JScript 5.5 and later, you should use encodeURI( ) and encodeURIComponent( ...