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JavaScript Programming Essentials Tutorial

Learn about JavaScript data types, declaring variables, calling functions, and working with variables and data in this comprehensive tutorial. Understand numeric, string, boolean, and null variable types. Explore creating and using JavaScript functions efficiently.

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JavaScript Programming Essentials Tutorial

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  1. Tutorial 10 – Session 2 Programming with JavaScript

  2. Objectives Learn about JavaScript data types Declare and work with variables Create and call a JavaScript function New Perspectives on HTML and XHTML, Comprehensive

  3. Working with Variables A variable is a named item in a program that stores information Most JavaScript programs use variables to represent values and text strings New Perspectives on HTML and XHTML, Comprehensive

  4. Declaring a JavaScript Variable You can declare variables with any of the following JavaScript commands: var variable; var variable = value; variable = value; where variable is the name of the variable and value is the initial value of the variable. The first command creates the variable without assigning it a value; the second and third commands both create the variable and assign it a value New Perspectives on HTML and XHTML, Comprehensive

  5. Working with Variables and Data JavaScript variable types: Numeric variables String variables Boolean variables Null variables You must declare a variable before using it New Perspectives on HTML and XHTML, Comprehensive

  6. Working with Variables and Data Numeric variable- any number, such as 13, 22.5, etc. Can also be expressed in scientific notation String variable- any group of text characters, such as “Hello” or “Happy Holidays!” Must be enclosed within either double or single quotations (but not both) Boolean variable- accepts only true and false values Null variable- has no value at all New Perspectives on HTML and XHTML, Comprehensive

  7. Working with Variables and Data JavaScript is a weakly typed language The + symbol can be used with either numeric values or text strings var total = 5 + 4; var emLink = "cadler" + "@" + "mpl.gov"; New Perspectives on HTML and XHTML, Comprehensive

  8. Creating a JavaScript Function A function is a collection of commands that performs an action or returns a value A function name identifies a function Parameters are values used by the function The function is executed only when called by another JavaScript command function_name(parameter values) New Perspectives on HTML and XHTML, Comprehensive

  9. Creating a JavaScript Function New Perspectives on HTML and XHTML, Comprehensive

  10. Creating a Function to Return a Value For a function to return a value, it must include a return statement function function_name(parameters){ JavaScript commands return value; } New Perspectives on HTML and XHTML, Comprehensive

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