JavaScript Strings


The JavaScript string is an object that represents a sequence of characters.

A JavaScript string simply stores a series of characters

Example

var name = "Sachin";

You can use quotes inside a string, as long as they don't match the quotes surrounding the string

var msg = "Hello World !";
var msg = "Hello 'World !'";
var msg = 'Hello "World !"';

String Length

The length of a string is found in the built in property length.

Example

<script type="text/javascript">
var txt = "Welcome to JavaScript Tutorial";
var strleng = txt.length;
document.write(strleng);
</script>
Output
30

Special Characters

Because strings must be written within quotes, JavaScript will misunderstand this string:

 var str = "Creating a "String" object."

The string will be chopped to "Creating a ".

The solution to avoid this problem, is to use the \ escape character.

The backslash escape character turns special characters into string characters:

 var str = "Creating a \"String\" object."

The escape character ( \ ) can also be used to insert other special characters in a string.

This is the lists of special characters that can be added to a text string with the backslash sign:

CodeOutputs
\'single quote
\"double quote
\\backslash
\nnew line
\rcarriage return
\ttab
\bbackspace
\fform feed

Strings Can be Objects

The String object let's you work with a series of characters and wraps Javascript's string primitive data type with a number of helper methods.

Syntax

var val = new String(string);

Example

<script type="text/javascript">
var str = new String("Welcome to JavaScript Tutorial");
document.write(str);
</script>
Output
Welcome to JavaScript Tutorial

String Properties

PropertyDescription
constructorReturns the function that created the String object's prototype
lengthReturns the length of a string
prototypeAllows you to add properties and methods to an object

String Methods

MethodDescription
charAt()Returns the character at the specified index (position)
charCodeAt()Returns the Unicode of the character at the specified index
concat()Joins two or more strings, and returns a copy of the joined strings
fromCharCode()Converts Unicode values to characters
indexOf()Returns the position of the first found occurrence of a specified value in a string
lastIndexOf()Returns the position of the last found occurrence of a specified value in a string
localeCompare()Compares two strings in the current locale
match()Searches a string for a match against a regular expression, and returns the matches
replace()Searches a string for a value and returns a new string with the value replaced
search()Searches a string for a value and returns the position of the match
slice()Extracts a part of a string and returns a new string
split()Splits a string into an array of substrings
substr()Extracts a part of a string from a start position through a number of characters
substring()Extracts a part of a string between two specified positions
toLocaleLowerCase()Converts a string to lowercase letters, according to the host's locale
toLocaleUpperCase()Converts a string to uppercase letters, according to the host's locale
toLowerCase()Converts a string to lowercase letters
toString()Returns the value of a String object
toUpperCase()Converts a string to uppercase letters
trim()Removes whitespace from both ends of a string
valueOf()Returns the primitive value of a String object

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