Decision Making in JavaScript.

A conditional/decision-making construct evaluates a condition before the instruction(s) are executed.

Decision Making statements are if, else, elseif and switch these statements are used in making decisions.

if..else statements

if..else statements is used where you want to execute a set of code when a condition is true and another if the condition is not true.

Syntax:

if (condition)
{
  code to be executed if condition is true
}
else
{
  code to be executed if condition is false
}

Example of if..else

var a=10;
if (a==10)
{
  echo "Yes the value is 10"; 
}
else
{
  echo "No the value is not 10"; 
}

elseif statements

elseif statements is used where you want to execute a some code if one of several conditions are true use the elseif statement.

Syntax:

if (condition)
{
  code to be executed if condition is true
}
elseif (condition)
{
  code to be executed if condition is true;
}
else
{
  code to be executed if condition is false
}

Example of elseif

var a=10;
if (a==20)
{
  echo "Yes the value is 20"; 
}
elseif(a==10)
{
  echo "Yes the value is 10"; 
}
else
{
  echo "No you are wrong"; 
}

switch statements

switch statements is used where you want to execute one block of code out of many.

Syntax:

switch (value)
{
case value1:
  code to be executed if value = value1;
  break;  

case value2:
  code to be executed if value = value2;
  break;

default:
  code to be executed
  if value is different 
  from both value1 and value2;
}

Example of switch:

var a=10;
switch ( a )
{
case 10:
  code to be executed if var a=10;
  break;  

case 20:
  code to be executed if var a=20;
  break;

default:
  code to be executed
  if value is different 
  from both value1 and value2;

}

We'll discuss extensively in the other topics.