String |
support for strings |
Availability
JavaScript 1.0; JScript 1.0; ECMAScript v1
Inherits from/Overrides
Inherits from Object
Constructor
new String(s) // Constructor function
String(s) // Conversion function
Arguments
- s
-
The value to be stored in a String object or converted to a primitive
string.
Returns
When String( ) is used as a constructor with the
new operator, it returns a String object, which
holds the string s or the string
representation of s. When the
String( ) constructor is used without the
new operator, it simply converts
s to a primitive string and returns the
converted value.
Properties
- length
-
The number of characters in the string.
Methods
- charAt( )
-
Extracts the character at a given position from a string.
- charCodeAt( )
-
Returns the encoding of the character at a given position in a string.
- concat( )
-
Concatenates one or more values to a string.
- indexOf( )
-
Searches the string for a character or substring.
- lastIndexOf( )
-
Searches the string backward for a character or substring.
- match( )
-
Performs pattern matching with a regular expression.
- replace( )
-
Performs a search-and-replace operation with a regular expression.
- search( )
-
Searches a string for a substring that matches a regular expression.
- slice( )
-
Returns a slice or substring of a string.
- split( )
-
Splits a string into an array of strings, breaking at a specified
delimiter string or regular expression.
- substring( )
-
Extracts a substring of a string.
- substr( )
-
Extracts a substring of a string. A variant of substring(
).
- toLowerCase( )
-
Returns a copy of the string, with all characters converted to
lowercase.
- toString( )
-
Returns the primitive string value.
- toUpperCase( )
-
Returns a copy of the string, with all characters converted to
uppercase.
- valueOf( )
-
Returns the primitive string value.
Static Methods
- String.fromCharCode( )
-
Creates a new string using the character codes passed as arguments.
HTML Methods
Since JavaScript 1.0 and JScript 1.0,
the String class has defined a number of methods that return a string
modified by placing it within HTML tags. These methods have never
been standardized by ECMAScript but can be useful in both client-side
and server-side JavaScript code that dynamically generates HTML. If
you are willing to use nonstandard methods, you might create the HTML
source for a bold, red hyperlink, with code like this:
var s = "click here!";
var html = s.bold( ).link("javascript:alert('hello')").fontcolor("red");
Because these methods are not standardized, they do not have
individual reference entries in the pages that follow:
- anchor( name)
-
Returns a copy of the string, in an <a
name=> environment.
- big( )
-
Returns a copy of the string, in a <big>
environment.
- blink( )
-
Returns a copy of the string, in a <blink>
environment.
- bold( )
-
Returns a copy of the string, in a <b>
environment.
- fixed( )
-
Returns a copy of the string, in a <tt>
environment.
- fontcolor( color)
-
Returns a copy of the string, in a <font
color=> environment.
- fontsize( size)
-
Returns a copy of the string, in a <font
size=> environment.
- italics( )
-
Returns a copy of the string, in a <i>
environment.
- link( url)
-
Returns a copy of the string, in a <a href=>
environment.
- small( )
-
Returns a copy of the string, in a <small>
environment.
- strike( )
-
Returns a copy of the string, in a <strike>
environment.
- sub( )
-
Returns a copy of the string, in a <sub>
environment.
- sup( )
-
Returns a copy of the string, in a <sup>
environment.
Description
Strings
are a primitive data type in JavaScript. The String class type exists
to provide methods for operating on primitive string values. The
length property of a String object specifies the
number of characters in the string. The String class defines a number
of methods for operating on strings: there are methods for extracting
a character or a substring from the string or searching for a
character or a substring, for example. Note that JavaScript strings
are immutable: none of the methods defined by
the String class allows you to change the contents of a string.
Instead, methods like String.toUpperCase( ) return
an entirely new string, without modifying the original.
In Netscape implementations of JavaScript 1.2 and later, strings
behave like read-only arrays of characters. For example, to extract
the 3rd character from a string s, you could write
s[2] instead of the more standard
s.charAt(2). In addition, when the
for/in statement is applied to a string, it
enumerates these array indexes for each character in the string.
(Note, however, that the length property is not
enumerated, as per the ECMAScript specification.) Because this
string-as-array behavior of Netscape's implementations is not
standard, you should usually avoid using it.
See Also
Chapter 3
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