if else

Summary

Conditionally executes a group of statements, depending on the value of an expression.

if ( condition1 ) {
     statement1
} else if ( condition2 ) {
     statement2
} else {
     statement3
}

condition1: Required. A Boolean expression. If condition1 is null or undefined , condition1 is treated as false.
statement1: Optional. The statement to be executed if condition1 is true. Can be a compound statement.
condition2: The condition to be evaluated.
statement2: Optional. The statement to be executed if condition2 is true. Can be a compound statement.
statement3: If both condition1 and condition2 are false , this statement is executed.

The following code shows how to use if , if else , and else.

It is good practice to enclose statement1 and statement2 in braces ({}) for clarity and to avoid inadvertent errors.

var z = 3;
 if (x == 5) {
     z = 10;
 }
 else if (x == 10) {
     z = 15;
 }
 else {
     z = 20;
 }