In this article we will learn various property and functions of string in JavaScript.
Property and function of string in JavaScript
In this article we will learn various property and functions
of string object in JavaScript. As we know that JavaScript is object oriented
language and everything is treated as object in JavaScript. String is also one
type of object in JavaScript. It has only one property called “length” and few
functions. We will understand them one by one with example.
Length property
Length property of string object returns the number of character
it contains. Here is one example of length property of string.
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="JavaScript.aspx.cs" Inherits="JavaScript.JavaScript" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
</head>
<body>
<form id="form1" runat="server">
<script>
var a = "SouravKayal";
alert(a.length);
</script>
</form>
</body>
</html>
This is the output of above example.
charAt() function
This function returns the character at specific position. It
takes one integer argument which denoted index of string. Here is code snippet
to understand charAt() function.
<body>
<form id="form1" runat="server">
<script>
var a = "SouravKayal";
alert(a.charAt(0));
</script>
</form>
</body>
IndexOf function
IndexOf() function returns the index of a particular
character. In below example we are trying to find the index of ‘k’ from ‘a’
string.
<body>
<form id="form1" runat="server">
<script>
var a = "SouravKayal";
alert(a.indexOf('K'));
</script>
</form>
</body>
Here is sample output.
toLowerCase() function
This function is used to change the string to lower case
from upper case. In example string there are two upper case characters and by
using this function all characters are changed into lowercase.
<body>
<form id="form1" runat="server">
<script>
var a = "SouravKayal";
alert(a.toLowerCase());
</script>
</form>
</body>
toUpperCase() function
This function is to make the string to uppercase. This is sample example of toUpperCase()
function.
<body>
<form id="form1" runat="server">
<script>
var a = "SouravKayal";
alert(a.toUpperCase());
</script>
</form>
</body>
substring() function
Sometimes it is necessary to get the part of long string. In
this situation we can use substring() fnction. Here is working example of
substring() function.
<body>
<form id="form1" runat="server">
<script>
var a = "SouravKayal";
alert(a.substring(2,5));
</script>
</form>
</body>
We are seeing that it has given the part of string started
by 2nd character
Replace() function
This function is used to replace some part of string by some
other string. It uses pattern matching concept to replace the part of the
string. In this example string we are replacing “Sourav” by “Replace” string.
<body>
<form id="form1" runat="server">
<script>
var a = "SouravKayal";
alert(a.replace("Sourav","Replaced"));
</script>
</form>
</body>
Conclusion:-
In this article we have seen various string handling
function in JavaScript. Hope you understood the concept. Basically we can use
those functions to validate user’s input.