JavaScript If Else Statement
Conditional Statements
Conditional statements are used to perform different actions based on different conditions.
Very often when you write code, you want to perform different actions for different decisions.
You can use conditional statements in your code to do this.In JavaScript we have the following conditional statements:
- Use if to specify a block of code to be executed, if a specified condition is true
- Use else to specify a block of code to be executed, if the same condition is false
- Use else if to specify a new condition to test, if the first condition is false
- Use switch to specify many alternative blocks of code to be executed
if (condition) {
// block of code to be executed if the condition is true
}
The if Statement
Use the if statement to specify a block of JavaScript code to be executed if a condition is true.
if (condition) {
// block of code to be executed if the condition is true
}
Note that if is in lowercase letters. Uppercase letters (If or IF) will generate a JavaScript error.
The else Statement
Use the else statement to specify a block of code to be executed if the condition is false.
if (condition) {
// block of code to be executed if the condition is true
} else {
// block of code to be executed if the condition is false
}
if (hour < 18) {
greeting = "Good day";
} else {
greeting = "Good evening";
}
The else if Statement
Use the else if statement to specify a new condition if the first condition is false.
if (condition1) {
// block of code to be executed if condition1 is true
} else if (condition2) {
// block of code to be executed if the condition1 is false and condition2 is true
} else {
// block of code to be executed if the condition1 is false and condition2 is false
}
if (time < 10) {
greeting = "Good morning";
} else if (time < 20) {
greeting = "Good day";
} else {
greeting = "Good evening";
}
