Basics of JS
Variable Declaration:

    var myVariable = "David";
    var myNumber = 300;
PopUp Window

    alert(myVariable);
Input Box

    prompt()    //alert with input box
Console

    console.log('this is a log to console:', myNumber)
Assignments

    var name = 'Guy' , age='46';
    var age1 = 30, age2 = age1 + 4
When a variable is not defined - 

    Uncaught ReferenceError: age1 is not defined
When a variable was called before it was defined

undefined
A variable can change its type in runtime

var foo = 42;   // defined as a number
foo = 'guy';    // now its a string
foo = true;     // not its a boolean
Remarks (like c)

//  single line

/*
  - range-multiline
*/
Operators

regular         + - * / 
comparison      ===         Type and Value (77 === '77' -> false)
comparison      ==          Value only (77 == '77' -> true)
not             ! 
not equal       !===
maths           x += y      x = x + y
                x -= y      x = x - y
                x *= y      x = x * y
                x /= y      x = x / y
reminder        x%=y        x = x % y
exponent        x**=y       x = x ** y
Logical Operators
Operator Usage description
Logical AND (&&) exp1 && exp2 Only if both are TRUE
Logical OR (||) exp1 || exp2 at least one of them is TRUE
Logical NOT (!) !exp is not TRUE
Precendence ex1 && ex2 || ex3 && ex4 AND checked before OR
Text concatenation

console.log('guy' + ' ' + 'and ' + 'Natasha' )
Conditions

if(something === something ){

}else if{

}else{

}
Ternary Operator
a short way to write a condition

var beverage = (age >= 21) ? "Beer" : "Juice";


var resultHolder = (condition) ? TRUE value : FALSE value;
With multiple conditions:

var resultHolder = (condition) ? value1
                :(condition) ? value2
                :(condition) ? value3
                :value1;
Functions

// Define function
function myFunction(arg1,arg2){
    var result = arg1 * arg2;
    return result;
}
Call the function

myFunction(var1,var2);
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