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javascript function ujjwal matoliya.pptx

This document discusses functions in JavaScript, describing them as reusable code segments that improve modularity and readability of programs. It covers function definition, parameters, return statements, and expressions, emphasizing the benefits of reusability and ease of understanding. Examples illustrate how to declare and call functions, including the use of anonymous functions.

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1 Atal Bihari Vajpayee Vishwavidyalaya Session 2020-21 Subject :-Internet Technologies Submitted By Ujjwal Matoliya Topic :-functions
2 ADD A FOOTER Function Function Definition Calling a Function Function Parameters Function Return Function Expressions 1
Function 3 A function is a group of reusable code which can be called anywhere in your program. This eliminates the need of writing the same code again and again. It helps programmers in writing modular codes. Functions allow a programmer to divide a big program into a number of small and manageable functions. 2
4 3 Function Declaretion The most common way to define a function in JavaScript is by using the function keyword, followed by a unique function name, a list of parameters (that might be empty), and a statement block surrounded by curly braces. Syntax <script type = "text/javascript"> <!-- function functionname(parameter-list) { statements } //--> </script> <script type = "text/javascript"> <!-- function sayHello() { alert("Hello there"); } //--> </script>
Calling a Function 5 4
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7 ADD A FOOTER Function Parameters A function can also be declared with parameters. A parameter is a value that is passed when declaring a function. 6
8 ADD A FOOTER program to add two numbers using a function Parameters 7
9 ADD A FOOTER Function Return A JavaScript function can have an optional return statement. This is required if you want to return a value from a function. This statement should be the last statement in a function. 8
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12 ADD A FOOTER Function Expressions In Javascript, functions can also be defined as expressions. In the above program, variable x is used to store the function. Here the function is treated as an expression. And the function is called using the variable name. The function above is called an anonymous function. 11
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14 ADD A FOOTER Benefits of Using a Function Function makes the code reusable. You can declare it once and use it multiple times. Function makes the program easier as each small task is divided into a function. Function increases readability. 13
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