CS-3432 Electronic Commerce Lecture – 13 Sikandar Shujah Toor

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onmouseover & onmouseout

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Operators in JavaScript + For addition of two numbers and concatenation of two strings - for subtraction of two numbers * for multiplication of two numbers / for division of two numbers % modulus (calculating the remainder) ++ increment in number -- decrement in number

Logical Operators && logical and || logical or ! logical not if(x<y&&x<z) { any statement } if(!false){ statement }

Comparison Operators == Equal != not equal < Less than <= less than equal > Greater than >= Greater than equal

Javascript Example alert("Thank you for visiting our web site!") Java Script Example

Writing on a Page example-writing on the page <!-- document.write("Hello! Thank you for visiting our site.") //-->

Writing on a Page

Functions Definition Function is a block of code which is executed when someone calls it Defined as follows function my1stfunction(arg1, arg2, arg3) { // some code } When called, variables and arguments must be in expected order

Displaying System Date function displayDate(){ document.getElementById(“systemdt”).innerHTML=Date(); } My First JavaScript This is a paragraph. Display Date

<!-- function Addit(){ var num1=document.Calform.fst.value; var num2=document.Calform.scnd.value; alert(parseFloat(num1)+parseFloat(num2)); } function minus(){ var num1=document.Calform.fst.value; var num2=document.Calform.scnd.value; alert(parseFloat(num1)-parseFloat(num2)); } //--> Add and Subtract Calculator 1st Number: 2nd Number: Simple Calculator

Simple Calculator – Add

Simple Calculator – Minus

Loops Loops executes a block of code repeatedly until a condition is met Following types of loops present in JS For loop for(intialization;condition;increment) {statements} While loop while(codition){statements} Do while loop do{statements}while(condition) Do-while loop executes at least once

For Loop Using the For Loop for(i=1;i<7;i++) document.write(" For Loop Example "+i+“ !! ");

For Loop Example

While Loop Using the While Loop <!-- var i = 1; while (i < 7){ document.write(" While Loop Example "+i+"!! "); ++i; } //-->

While Loop Example

Do-while Loop Using the While Loop <!-- var i = 1; do { document.write(" Do-While Loop Example "+i+"!! "); ++i; } while (i < 1); //--> Loop executed once although the condition is false from the beginning

Do-while Loop Example

Java Script Objects Everything in Java Script is an Object which is a combination of data, properties and methods Properties are the values associated with the object Methods are the actions which can be performed on the object New objects can be inherited with “new” key word person = new Object() Object Properties can be set / retrieved by using “.” after object name person.name=“Uzair”; Methods can be called by the same “.” after object name var name = persone.getName();

Some Predefined JS Objects Global Array String Math Date … etc.

Example of Math object Using the Math object Using the Math object <!-- document.write("Math.PI :" +Math.PI +" "); document.write("Math.LN2 :"+Math.LN2+" "); document.write("Math.sin(90) :"+Math.sin(90)+" "); document.write("Math.random() :"+Math.random()+" "); document.write("Math.pow(2,3) :"+Math.pow(2,3)+" "); document.write("Math.min(123,133): "+Math.min(123,133)+" "); //-->

Math Object Example

Array Object Using Arrays Using Arrays <!-- myArray=[0,1,2,3,4,5,6,7,8,9,10]; document.write("myArray: first element " +myArray[0]+" "); document.write("myArray.toString(): "+myArray.toString()+" "); document.write("myArray.join(':'): "+myArray.join(':')+" "); document.write("myArray.reverse(): "+myArray.reverse()+" "); document.write("myArray.sort(): "+myArray.sort()+" "); //-->

Array Object