if (condition)
{
code to execute if condition true
}

<script type="text/javascript"<

var name = "Vyom";

if (name = "Vyom")
{
document.write("Hello Rajesh");
}
</script<

<script type="text/javascript">
//Write a "Good morning" greeting if
//the time is less than 10

var d=new Date()
var time=d.getHours()

if (time<10)
{
document.write("Good morning")
}
</script>

<script type="text/javascript">
//Write "Lunch-time!" if the time is 11

var d=new Date()
var time=d.getHours()

if (time==11)
{
document.write("Lunch-time!")
}
</script>

if (condition)
{
code to execute if condition true
}

<script language="javascript">
var a = "1234abc";
if(a == "adcdefa")
{
document.write(" inside if statement ");
}
else
{
document.write(" inside else part of statement ");
}
</script>

<script language="javascript">
//If the time is less than 10,
//you will get a "Good morning" greeting.
//Otherwise you will get a "Good day" greeting.

var d = new Date()
var time = d.getHours()

if (time < 10)
{
document.write("Good morning!")
}
else
{
document.write("Good day!")
}
</script>

if (condition)
{
code to execute if condition true
}
else if (condition)
{
code to execute if 2nd condition true
}
else
{
code to execute if above are false
}

<script language="javascript">
var name = "Mary";

if (name = "John"){
document.write("Hello John ");
}
else if (name = "Peter")
{
document.write("Hello Peter");
}
else {
document.write("Hello Stranger");
}
</script>

<script language="javascript">
var d = new Date()
var time = d.getHours()
if (time<10)
{
document.write("Good morning")
}
else if (time>10 && time<16)
{
document.write("Good day")
}
else
{
document.write("Hello World!")
}
</script>