Function is the heart of java script. If you will do anythings in java script then you have to write function.
While working on asp.net project so many time we get scenario to retun value from some function and display somewhere.
But here we can do like C# method. We have to include retun at end of function like this
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Function.aspx.cs" Inherits="Javascript_Test_Function" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> <script type="text/javascript"> function sayHello() { var msg = "I m from Javacript"; return msg; } function doSomething() { var msg1 = sayHello(); document.getElementById('<%=txtMsg.ClientID %>').value = msg1; } </script> </head> <body> <form id="form1" runat="server"> <div> <asp:Button ID="btnclick" runat="server" OnClientClick="doSomething();return false;" Text="Click Here" /> <br /> <br /> <asp:TextBox ID="txtMsg" runat="server" /> </div> </form> </body> </html>