JavaScript StringObject

The String object is used to handle existing character blocks.

JavaScript Strings

A string is used to store a series of characters like "John Doe".

A string can use single or double quotes:

Examples

var carname="Volvo XC60";
var carname='Volvo XC60';

You can access any character in a string using its position (index):

Examples

var character=carname[7];

String indexes start from zero, so the first character of a string is

You can use quotes in a string, as in the example below:

Examples

var answer="It's alright";
var answer="He is called 'Johnny'";
var answer='He is called "Johnny"';

Or you can use escape characters (\) in a string to use quotes:

Examples

var answer='It\'s alright';
var answer="He is called \"Johnny\"";

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String

The String object uses the length propertylengthto calculate the length of a string:

Examples

var txt="Hello World!";
document.write(txt.length);

var txt="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
document.write(txt.length);

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Find a String in a String

Strings use indexOf() to locate the first occurrence of a specified character in a string:

Examples

var str="Hello world, welcome to the universe.";
var n=str.indexOf("welcome");

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Returns -1 if the corresponding character is not found.

The lastIndexOf() method starts searching from the end of the string for the position where the string appears.

Content Matching

match()The function is used to find a specific character in a string and returns that character if found.

Examples

var str="Hello world!";
document.write(str.match("world") + "<br>");
document.write(str.match("World") + "<br>");
document.write(str.match("world!"));

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Replace Content

replace()The method replaces some characters with other characters in a string.

Examples

str="Please visit Microsoft!"
var n=str.replace("Microsoft","Example");

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String Case Conversion

Use functions for string case conversiontoUpperCase() / toLowerCase():

Examples

var txt="Hello World!";       // String
var txt1=txt.toUpperCase(); // txt1 text will be converted to uppercase
var txt2=txt.toLowerCase(); // txt2 text will be converted to lowercase

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Convert String to Array

Strings use thesplit()function to convert to an array:

Examples

txt="a,b,c,d,e"   // String
txt.split(","); // separated by commas
txt.split(" "); // separated by spaces
txt.split("|"); // separated by vertical bars

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Special Characters

In JavaScript, you can use backslash (\) to insert special symbols, such as apostrophes, quotes, and other special symbols.

Look at the following JavaScript code:

var txt="We are the so-called "Vikings" from the north.";
document.write(txt);

In JavaScript, strings are started and stopped with single or double quotes. This means the above string will be cut into: We are the so-called

To solve the problem above, you can use a backslash to escape the quotes:

var txt="We are the so-called \"Vikings\" from the north.";
document.write(txt);

JavaScript will output the correct text string: We are the so-called "Vikings" from the north.

The table below lists other special characters that can be escaped with a backslash:

Code Output
\' Single quote
\" Double quote
\\ Backslash
\n Newline
\r Carriage return
\t tab
\b Space
\f Form feed

String Properties and Methods

Properties:

  • length
  • prototype
  • constructor

Methods:

  • charAt()
  • charCodeAt()
  • concat()
  • fromCharCode()
  • indexOf()
  • lastIndexOf()
  • match()
  • replace()
  • search()
  • slice()
  • split()
  • substr()
  • substring()
  • toLowerCase()
  • toUpperCase()
  • valueOf()

For more methods and properties, refer to:JavaScript String Object

Other Extensions