If else Statement
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If else Statement
The if statement is used in JavaScript to execute the code if condition is true or false. There are three forms of if statement.
- If Statement
- If else statement
- if else if statement
JavaScript If statement
if is most basic statement of Decision making statement. It tells to program to execute a certain part of code only if particular condition or test is true.
Syntax
Syntax
if(expression)
{
//set of statements
}
Example
<script>
var a=10;
if(a>5)
{
document.write("value of a is greater than 5");
}
</script>
JavaScript if-else statement
In general it can be used to execute one block of statement among two blocks.
Syntax
if(expression)
{
//set of statements
}
else
{
//set of statements
}
Example of if..else statement
<script>
var a=40;
if(a%2==0)
{
document.write("a is even number");
}
else{
document.write("a is odd number");
}
</script>
Result
a is even number
JavaScript If...else if statement
It evaluates the content only if expression is true from several expressions.
Syntax
if(expression1)
{
//content to be evaluated if expression1 is true
}
else if(expression2)
{
//content to be evaluated if expression2 is true
}
else
{
//content to be evaluated if no expression is true
}
Example of if..else if statement
<script>
var a=40;
if(a==20)
{
document.write("a is equal to 20");
}
else if(a==5)
{
document.write("a is equal to 5");
}
else if(a==30)
{
document.write("a is equal to 30");
}
else
{
document.write("a is not equal to 20, 5 or 30");
}
</script>
Result
a is equal to 40
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