Javascript

Question 1

Javascript

Answer 1

https://developer.mozilla.org/en-US/docs/Web/JavaScript

Question 2

alert( )

Answer 2

Pop up message to give user an alert.

Question 3

Data Type

Answer 3

Don’t have to specify anything specifically (most of the time). We can force it to recognize certain characters are numbers though.

Data types include “string”, number, boolean.

You can check data type using typeOf( ‘variable here’ )

Question 4

Variable and Constants.

Answer 4

Variables are declared with ‘var’ and ‘let’
Constants are declared with ‘const’.

‘let’ is preferred in most situation while declaring a variable.

Question 5

Variable naming

Answer 5

Please use Camel Casing.

Question 6

String concatenate

Answer 6

Just use ‘+’ sign between your strings.

Question 7

String length

Answer 7

string.length;

Question 8

Slicing and Extracting parts of String

Answer 8

string.slice( x , y )

x - the start of slicing, the string starting from zero (always keep in mind)
y - index of character upto which we should cut, not including that particular character.

Example - let a = “Koolaid”;

a.slice(4, 7) - Output —-> aid

Question 9

Arithematic

Answer 9

+, -, *, /, %

% - remainder

++ increament
– decreament

Math.round( ) ————> Generate random number from 0 to 0.99

Math.floor( ) —————> Rounds down a number to nearest lower integer

Question 10

Function call and Return

Answer 10

function functionName( (argument) )
{
        code here;
        return some-variable-here;
}

Question 11

Random Number

Answer 11

Random number between 1 and 5

Math.floor( Math.random( ) * 5 + 1 );

math.random( ) * 5 —–> generates a number from 0 to 4.99

Question 12

Conditional statements and Comparators

Answer 12

If{ } else { }

comparators are ‘ < ‘ , ‘ > ‘, ‘ === ‘, ‘ <= ‘, ‘ >= ‘, ‘ !== ‘

’ == ‘ compares but doesnt comapre data type, and ‘ === ‘ compares the value as well as data types.

Combine conditions using ‘ && ‘, ‘ || ‘, ‘ ! ‘ (not).

Question 13

Array

Answer 13

a= [1, 2, 3, 4, 5, 6];
a=[ ];

a[2] = 3;
because, arrays and strings start index from zero, 0.

Question 14

Looping

Answer 14

while ( condition -> true ) { Loops code executes; }

for ( var initial, var conditional, var increment ) { Loop code here; }