Javascript conditional statement

When you need to make program to make decisions, conditional statements are used. In javascript we have following conditional statements:

•  if statement - use this statement to execute some code only if a specified condition is true
• if...else statement - use this statement to execute some code if the condition is true and another code if the condition is false
•  if...else if....else statement (nesting of if else)- use this statement to select one of many blocks of code to be executed
• switch statement - use this statement to select one of many blocks of code to be executed

If Statement:

Executes the code if a specific code is true

Syntax:

if(condition)
{
code
}

Example:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Siple Javascript conditions</title>
</head>

<body>
<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

<script>
function myFunction()
{
var x="";
var day=new Date().getDay();
if (day=="6")
  {
  x="Happy Weekend!";
  }
 document.getElementById("demo").innerHTML=x;
}
</script>

</body>
</html>

If...else Statement

Use if..else statement to execute some code if a condition is true and another code if the condition is false

Syntax:
if (condition)
  {
  code
  }
else
  {
  code
  }

Example:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Siple Javascript conditions</title>
</head>

<body>
<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

<script>
function myFunction()
{
var x="";
var day=new Date().getDay();
if (day=="6")
  {
  x="Happy Weekend!";
  }
  else{
      x="Have a Good day";
  }

document.getElementById("demo").innerHTML=x;
}
</script>

</body>
</html>

If...else if...else Statement

Use the if....else if...else statement to select one of several blocks of code to be executed.

Syntax:

if (condition1)
  {
  code
  }
else if (condition2)
  {
  code
  }
else
  {
  code
  }

Example:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Siple Javascript conditions</title>
</head>

<body>
<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

<script>
function myFunction()
{
var x="";
var day=new Date().getDay();
if (day=="6")
  {
  x="Happy Weekend!";
  }
  else if(day == "1"){
      x="Have a Good start of a week";
  }
  else
  {
      x="Have a good day";
  }

document.getElementById("demo").innerHTML=x;
}
</script>

</body>
</html>