Read05.md

Comparison and logical operators

CALCULAT E ANO WRITE OUT THE EX PIRY DETAILS FOR THE OFFER

• var expiryMsg; II Message displ ayed t o users
• var today ; II Today's dat e
• var el Ends ; II The element that shows the message about the offer endi ng

Functions allow you to group a set of related statements together that represent a single task.

Functions can take parameters (informatiorJ required to do their job) and may return a value.

An object is a series of variables and functions that represent something from the world around you.

0JavaScript also has several built-in objects such as String, Number, Math, and Date. Their properties and methods offer functionality that help you write scripts.

Arrays and objects can be used to create complex data sets (and both can contain the other).

Evaluating conditions and conditional statements

Summary

No	----
1	The if-else and if statements
2	Block of statements
3	Conditional expression
4	Comparison between objects
5	The switch statement

The if-else and if statements ~ if (condition ) then-statement else else-statement • condition is an expression of type boolean, i.e., a conditional expression that is evaluated to true or false • then-statement is a single statement (also called the then-branch of the if-else statement) • else-statement is a single statement (also called the else-branch of the if-else statement)~

Evaluating conditions

one of the comparison operators (==, !=, >, <, >=, or <=) applied to variables (or expressions) of a primitive type;

Example: int a, b, c; ... if (a > b + c)

a complex boolean expression, obtained by applying the boolean operators !, &&, and || to simpler expressions;

Example: int a, b, c, d; String answer; ... if ((a > (b+c)) || (a == d) && !answer.equalsIgnoreCase("YES"))

else-statement

condition is an expression of type boolean, i.e., a conditional expression that is evaluated to true or false

then-statement is a single statement (also called the then-branch of the if-else statement) else-statement is a single statement (also called the else-branch of the if-else statement)

Different Kinds of LoopsJavaScript 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. for/of - loops through the values of an iterable object
4. while - loops through a block of code while a specified condition is true
5. do/while - also loops through a block of code while a specified condition is true

for (statement 1; statement 2; statement 3) {
  // code block to be executed
}

Statement 1 is executed (one time) before the execution of the code block.

Statement 2 defines the condition for executing the code block.

Statement 3 is executed (every time) after the code block has been executed.