JAVAsCrIpT JAVAsCrIpT Mohamed Loey 

AgENdA Part I: Introduction Part II: JavaScript Syntax 

AgENdA Part I: Introduction  What is JavaScript?  JavaScript In HTML  JavaScript Can 

WHAT Is JAVAsCrIpT? • JavaScript is the first Web scripting language, developed by Netscape in 1995 • JavaScript is a scripting language. It is a lightweight, • JavaScript is a scripting language. It is a lightweight, but powerful, programming language. • JavaScript similarities to Java/C++ • JavaScript is Client-side web programming • JavaScript is the most popular programming language in the world. 

JAVAsCrIpT IN HTml • In HTML, JavaScripts must be inserted between and tags. • • JavaScripts can be put in the and in the section of an HTML page. • Two Ways to Insert JavaScript: 1. Internal script 2. External script sheet 

INTErNAl sCrIpT • Scripts can be placed in the or in the section of HTML, and/or in both. section of HTML, and/or in both. • Example: 

ExTErNAl sCrIpT sHEET • Scripts can also be placed in external files. • • External scripts are practical when the same code is used in many different web pages. • JavaScript files have the file extension .js. • To use an external script, put the name of the script file in the source (src) attribute of the tag 

ExTErNAl sCrIpT sHEET • Example: 

JAVAsCrIpT CAN • Change HTML Elements • • Change HTML Attributes • Change HTML Styles (CSS) • Validate Data 

AgENdA Part II: JavaScript Syntax  JavaScript is Case Sensitive  JavaScript Comments  JavaScript Variables  JavaScript Conditions  JavaScript Loops  JavaScript Arrays 

JAVAsCrIpT Is CAsE sENsITIVE • In JavaScript all identifiers are case sensitive. • The variables lastName and lastname, are two different variables. • The functions myFunction and myfunction, are two different functions. • JavaScript does not interpret Var; as var. 

JAVAsCrIpT CommENTs • Single Line Comments • Single line comments start with //. • Multi-line Comments • Multi-line comments start with /* and end with */. 

JAVAsCrIpT VArIAblEs • JavaScript uses the var keyword to define variables • Example: 

JAVAsCrIpT VArIAblEs • JavaScript uses the var keyword to define variables • Example: 

JAVAsCrIpT CoNdITIoNs • In JavaScript we have the following conditional statements: statements: 1. Use if to specify a block of code to be executed, if a specified condition is true 2. Use else to specify a block of code to be executed, if the same condition is false 3. Use else if to specify a new condition to test, if the first condition is false 4. Use switch to specify many alternative blocks of code to be executed 

JAVAsCrIpT CoNdITIoNs • Example: 

JAVAsCrIpT loops • JavaScript supports different kinds of loops: 1. for - loops through a block of code a number of times 2. for/in - loops through the properties of an object 3. while - loops through a block of code while a specified condition is true 4. do/while - also loops through a block of code while a specified condition is true 

JAVAsCrIpT loops • Example: 

JAVAsCrIpT ArrAys • JavaScript arrays are used to store multiple values in a single variable. • Example: 

JAVAsCrIpT FUNCTIoNs • A JavaScript function is a block of code designed to perform a particular task. • A JavaScript function is executed when "something" invokes it (calls it). • Example: 

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