Javascript

Conditions

Conditional statements  are used to perform 
different actions based on different conditions.

1. Condition if

IF
1. Can be used alone:
if (x > 0) 
{
document.write("The number is positive");
}
With if (condition){ ...}, the condition is true.


2. Can be used alone with else:
if (x > 0) 
{
document.write("The number is positive");
}
else
{
document.write("The number is negative");
}

3. Many "if" and many "else":
if (x > 0) 
{
document.write("The number is positive");
}
else if (x < 0) 
{
document.write("The number is negative");
}
else if (x == 0) 
{
document.write("The number is null");
}
else 
{
document.write("The variable is not a number! .. ");
}

2. Switch:

The syntax is:

switch(x)
{
case a:
  execute code1
  break;    
case b:
  execute code2
  break;
default:
  other if x is
  different from case a and a
}

The value  of "x" can be a bumber or a string.