Cis 215

Front 1

how is javascript limited in the way that other programming languages are not?

Back 1

-javascript only works inside another application - the web browser
-can't access local files
-can't directly access database
-can't access hardware, USB, etc

Front 2

what is javascript mainly used for

Back 2

to add interactivity to web pages

Front 3

when was javascript developed and by who with what company?

Back 3

1995 by brendan eich at netscape

Front 4

what is an interpreted language vs a compiled language and which type is javascript?

Back 4

complied languages need to be run through compiler where your code is converted into machine code so then it can run on the OS. with an interpreted code, the code is written and then interpreted by the, in the case of javascript, the browser.

Front 5

is Javascript case sensitive

Back 5

yes

Front 6

statements

Back 6

the grouping of javascript code, they are separate instructions or commands to say piece by piece what you want your script to do

Front 7

what punctuation mark is used to end a javascript statement

Back 7

semicolon

Front 8

is javascript whitespace sensitive?

Back 8

no

Front 9

syntax for commenting out single line

Back 9

// comment

Front 10

syntax for commenting on multiple lines

Back 10

/* this is for multiple
lines
of code */

Front 11

does the position of your javascript in your code matter and why

Back 11

yes, because the browser will render the code in the order in which its read, so for example, if you put an alert in the head, the browser will read the alert, and until you click ok, it will not render the rest of the page

Front 12

where is, for the most part, the best place to add your script tag and why

Back 12

just before the closing body tag of the html because the browser parses the code and if it's in the beginning, it's going to read the javascript before it reads the rest of the html which could slow down the load time

Front 13

variable

Back 13

a container for programming that holds a piece of computer memory and giving it a name so we can use it while our javascript is running

Front 14

example of syntax for javascript variable and what does the year represent

Back 14

var year; year represents the name of the variable

Front 15

what can you use for variable names

Back 15

letters, numbers, the underscore sign and the dollar sign

Front 16

can you start a variable name with a number

Back 16

no

Front 17

how do you set a value for a variable?

Back 17

add an equals sign and then give it a value

Front 18

example sytnax of variable with a value

Back 18

var year=2013;

Front 19

are variable names case sensitive

Back 19

yes

Front 20

if creating more than one variable at the same time, what is an example in syntax of another option other than giving each one it's one line

Back 20

var year=2011, month=10, day=31;

Front 21

example syntax of undefined variable

Back 21

var myVariable;

Front 22

example of syntax of defined variable

Back 22

var myVariable=200;

Front 23

conditional code syntax example

Back 23

if (condition) {// code goes here
//..
}

Front 24

what are paranthesis used for in conditional coding

Back 24

to mark out whatever the condition is

Front 25

what are braces used for in conditional coding

Back 25

to mark out what we'll do if the condition is true

Front 26

what must the condition always evaluate as

Back 26

true or false

Front 27

what are several statements surrounded by braces called?

Back 27

code block

Front 28

example of checking equality in a condition

Back 28

if (a ==200) {
// code goes here
//..
}

Front 29

when checking equality in javascript, what must you always use?

Back 29

either double or tripple equal signs

Front 30

example of full syntax using condition

Back 30

var amount=500;

if ( amount < 1000) {
alert("It's less than 1,000");
}

Front 31

what is this statement saying in layman's terms:

var amount=500;

if ( amount < 1000) {
alert("It's less than 1,000");
}

Back 31

you're declaring a variable of amount and setting it equal to 500

if the amount of is less than 500, then we'll execute whatever is between the braces

Front 32

syntax for conditional code if you want something else to happen if the if statement is false

Back 32

if ( ) {
//code goes here
//..
} else {
//otherwise, different code
}

Front 33

three ways to include javascript in html file

Back 33

1) code a separate external javascript file and code a script element in the head section of the HTML document to include that file
2) include javascript within the script element in the
head section
3)include javascript in an html document

Front 34

example syntax for external javascript file with script element in the head section

Back 34

<script src="calculate_mpg.js"></script>

Front 35

name given to variables, functions, objects, properties, methods and events so that you can refer to them in your Javascript code

Back 35

identifier

Front 36

rules for creating identifiers

Back 36

-can only contain letters, numbers, the underscore, and the dollar sign
-can't start with a number
-are case-sensitive
-can be any length
-can't be the same as reserved words
-avoid using global properties and methods as identifiers.

Front 37

what does it mean that you should give identifiers a meaningful name

Back 37

for instance, for a monthly investment, you should write it out as monthly_investment instead of abbreviating as mon_inv

Front 38

camel casing

Back 38

when identifiers have two words and the first letter of each word is capitalized except the first word, for example taxRate

Front 39

other option other than camel casing for identifiers

Back 39

using underscore between words, for example tax_rate

Front 40

what is an object

Back 40

has methods that perform functions that are related to the object as well as properties the represent the date of attributes that are associated with the object

Front 41

what does a method do

Back 41

performs a function or does an action

Front 42

what is a property

Back 42

a data item that relates to the object

Front 43

what does call mean in javaScript

Back 43

to execute

Front 44

syntax for calling a method of an object and break down in layman's terms

Back 44

ojbectName.methodName (parameters)

first code the object name, then add a dot operator (period), then the method name, then any parameters that the method requires

Front 45

three common methods of the window object

Back 45

alert(string)
prompt(string,default)
print()

Front 46

alert(string)

Back 46

method that displays a dialog box that contains the string that's passed to it by the parameter along with an OK button

Front 47

prompt(string,default)

Back 47

method that displays a dialogue box that contains the string the first parameter, the default value in the second parameter, and OK button, and a Cancel button. When the user enters a value and clicks OK, the value is returned as a string. Or if the user clicks Cancel, null is returned

Front 48

print()

Back 48

method that issues a print request to the browser

Front 49

example syntax for alert method

Back 49

window.alert("This is a test of the alert method");

Front 50

what is important to remember about the window object

Back 50

it is the global object of javaScript, which means it can be omitted when a method is written. for example , var userEntry = prompt("This is a test of the prompt method", 100);

Front 51

how to access a property of an object and example syntax

Back 51

code the property name after the dot operator. for example, alert(window.location);

Front 52

three primitive data types in javaScript

Back 52

1)number data type
2)string data type
3)Boolean data type

Front 53

number data type and example

Back 53

use to represent numerical data, for example 15, -21, 21.5, etc

Front 54

string data type

Back 54

use to store character data, for example "JavaScript", 'String Data'

Front 55

Boolean data type

Back 55

used to store true and fals values, for example true, false

Front 56

empty string

Back 56

quoted with two of the same quotation types one after the other, "", used to represent a string with no data in it

Front 57

numeric expression

Back 57

can be as simple as a single value or it can be a series of operations that result in a single value

Front 58

modulus operator and syntax

Back 58

calculates the remainder when the left value is divided by the right value, for example with the modulus operator 13 % 4, the result is 1

Front 59

increment operator and example

Back 59

adds 1 to the variable, for example, counter++

Front 60

decrement operator and example

Back 60

subtracts 1 from the variable, for example, counter--

Front 61

variable

Back 61

stores a value that can change as the program executes

Front 62

how to declare a numeric variable in JavaScript

Back 62

code the var (for variable) keyword followed by the identifier (or name) that you want to use for that variable

Front 63

assignment statement and example

Back 63

assigns a value to a variable. consists of a variable name, and assignment operator like =,and an expression. for example, var subtotal = 74.95;

Front 64

most useful assignment operators and what they do

Back 64

=, assigns the result of the expression of the variable
+=, adds the result of the expression to the variable

Front 65

how to declare variables and assign value to them

Back 65

var subtotal=74.95; //subtotal=74.95
var salesTax=subtotal * .1; //salesTax=7.4

Front 66

compound assignment operator

Back 66

+= modifies the variable on the left of the operator by adding the value of the expression on the right to the value of the variable on the left. example:

var subtotal = 74.95; // subtotal = 74.95
subtotal += 20.00; //subtotal =94.95

Front 67

three ways to increment a variable named counter by 1

Back 67

var counter = 1; //counter = 1
counter = counter + 1; //counter now =2
counter += 1; //counter now =3
counter ++; //counter now =4

Front 68

string literal

Back 68

value enclosed in quotation marks

Front 69

numeric literal

Back 69

string that isn't enclosed in quotation marks

Front 70

concatenation operator

Back 70

when + sign is use to add one string to the end of another string, example: "Ray" + "Harris" //"Ray Harris"
"Months: " + 120 //"Months: 120"

Front 71

How to declare string variables without assigning values to them

Back 71

var zipCode; // declares one variable
var lastName, state, zipCode; //delcare three variables

Front 72

How to declare string variables and assign values to them

Back 72

var firstName = "Ray", lastname="Harris"; //assigns two string values
var fullName = lastName + ", "+firstName; //fullName is "Harris, Ray"

Front 73

How to code compound assignment statements with string data

Back 73

var firstName = "Ray", lastName = "Harris";
var fullName = "lastName; //fullName is "Harris"
fullName += " , "; //fullname is "Harris, "
fullName += firstName; //fullname is "Harris, Ray"

Front 74

How to code compound assignment statements with mixed data

Back 74

var months = 120;
message = "Months: ";
message += months; //message is "Months: 120"

Front 75

Escape sequences that can be used in strings

Back 75

\n starts a new line in a string
\" Puts a double quotation mark in a string
\' Puts a single quotation mark in a string

Front 76

How escape sequences can be used in a string

Back 76

var message = "A valid variable name\cannot start with a number.";
var message="This isn\'t the right way to do this.";

Front 77

How to declare Boolean variables and assign values to them

Back 77

var isValid = false; //Boolean value is false

Front 78

parseInt(string)

Back 78

method that converts the string that's passed to it to an integer data type and returns that value. If it can't convert the string to an integer, it returns NaN.

Front 79

parseFloat(string)

Back 79

method that converts the string that's passed to it to a decimal data type and returns that value. If it can't convert the string to a decimal value, it returns NaN.

Front 80

examples that use the parseInt and parseFloat methods

Back 80

var entryA = prompt("Enter any value", 12345.6789);
alert(entryA); // displays 12345.6789
entryA = parseInt(entryA);
alert(entryA); //displays 12345

var entryB = prompt ("Enter any value", 12345.8789);
alert(entryB); //displays 12345.6789;
entryB = parseFloat(entryB);
alert(entryB); //displays 12345.6789;

var entryC = prompt("Enter any value", "Hello");
alert(entryC); //displays Hello
entryC = parseInt (entryC);
alerty(entryC); displays Nan

Front 81

control statements

Back 81

let you control how information is processed in JavaScript

Front 82

conditional expression

Back 82

returns a value of true of false based on the result of a comparison between two expressions

Front 83

what are the 6 relational operators

Back 83

== equal
!= not equal
< less than
<== less than or equal
> greater than
>== greater than or equal

Front 84

isNaN method

Back 84

determines whether a string value is a valid numeric value

Front 85

syntax of global isNaN method

Back 85

isNaN(expression)

Front 86

examples of isNaN method

Back 86

isNaN("Harris") //returns true since "Harris" is not a number
isNaN("123.45") //returns false since "123.45" can be converted to a number

Front 87

compound conditional expression

Back 87

use logical operators to combine conditional expressions

Front 88

the logical operators in order of presedence

Back 88

! NOT
&& AND
|| OR

Front 89

how does the AND operator work

Back 89

compound expression returns true if both expressions are true

Front 90

hows doe the OR operator work

Back 90

the compound expression returns true if either of the expressions are true

Front 91

how does the NOT operator work

Back 91

the value of the expression is reversed. for example, !isNaN returns true if the parameter is a number, so isNaN(10) returns false, but !isNaN(10) returns true

Front 92

to override the order of precedence when two or more logical operators are used in a conditional statement, what can you use

Back 92

parantheses

Front 93

if statements

Back 93

let you control the execution of statements based on the results of conditional expressions. brackets [ ] indicate a portion of the syntax that is optional. example: if (condition-1) {statements} [else if (condition-2) {statements}

Front 94

how to code an if clause

Back 94

code the keyword if followed by a conditional expression in parenthesis and a block of one or more statements in braces. if the conditional expression is true, its block of code will be executed and any remaining clauses in the if statement will be skipped over. this will continue until one of the else if expressions is true or they are all false.

Front 95

how to code an else clause

Back 95

code the keyword else followed by a block of one or more statements inside braces. this code will only be executed if all the conditional expressions in the if and else if clauses are false. if those expressions are false and there isn't an else clause, the if statement won't execute any code

Front 96

how to test whether a boolean variable is false

Back 96

if ( isValid == false) { }
if (!isValid == true) { }
if (!sValid) { }

Front 97

how to write a while loop statement

Back 97

var sumOfNumbers = 0;
var numberOfLoops = 5;
var counter = 1;
while (counte <= numberOfLoops) {
sumOfNumbers += counter; //adds counter to sumOfNumbers
counter==; //adds 1 to counter
}
alert(sumOfNumbers); //displays 15

Front 98

what is the difference between a loop and a do-while loop

Back 98

the condition is tested at the end of the loop instead of at the start

Front 99

example of do-while statement

Back 99

var sumOfNumbers = 0;
var numberOfLoops = 5;
var counter = 1;

do {
sumOfNumbers += counter; // add counter to SumOfNumbers
counter++; //adds 1 to counter
}

while (counter <= numberOfLoops);
alert(sumOfNumbers); //displays 15

Front 100

when to use a while loop vs. a do-while loop

Back 100

use do-while when you want to execute the statement in the loop at least once, and the while statement for other types of loops

Front 101

while loop that finds the average of a series of numbers

Back 101

var total = 0, count = 0, number;
number = parseFloat (prompt("Enter a number:") );
while ( !isNaN(number) ) {
total += number;
count++;
number = parseFloat (
prompt ("Enter another number or click Cancel
to stop:") );
}
var average = total / count;
alert("The average is: " + average);

Front 102

what does NaN mean

Back 102

the number isn't valid

Front 103

what does !NaN mean

Back 103

the number is valid

Front 104

for loop

Back 104

loop that is easier to code when the progress of the loops depends on a value that is incremented each time through loop

Front 105

syntax of a for statement and how it breaks down

Back 105

for ( countInitializaton; condition; incrementExpression ) {
statements
}

-counterInitialization is a counter (or index)
-then comes the condition that determines when the loop will end
-then comes an expression that determines how the loops should be incremented

Front 106

a for loop that adds the numbers 1 through 5

Back 106

var sumOfNumbers = 0;
var umberOfLoops = 5;
for (counter=1; counter <= numberOfLoops; counter++) {
sumOfNumbers += counter; //adds counter to sON
}
alert (sumOfNumbers); //displays 15