else and else if

Learn else and else if chains for alternative cases.

The else statement

To run a different block when the if condition is false you use else. The form is if (condition) { ... } else { ... }. Exactly one of the two blocks runs.

For example if (score >= 50) { console.log("Pass"); } else { console.log("Fail"); } prints "Pass" when score is at least 50 and "Fail" otherwise. The else block runs only when the if condition is false; it has no condition of its own.

else if chains

To test more than two cases you build a chain with else if. The first condition that is true has its block run; the rest are skipped. The form is if (c1) { ... } else if (c2) { ... } else { ... }.

For example a grade calculation: if (score >= 90) { ... "A" } else if (score >= 80) { ... "B" } else { ... "C" }. Conditions are checked top to bottom; the first true one determines the result. This structure is ideal for cases split into ranges.

Exercise Compute the grade letter

The score variable is set to 85. Write an if/else if/else chain: call console.log("A") when score >= 90, console.log("B") when score >= 80, otherwise console.log("C"). The output on a single line must be B.

Show example solution

const score = 85;
if (score >= 90) {
    console.log("A");
} else if (score >= 80) {
    console.log("B");
} else {
    console.log("C");
}

Test yourself

Write the else block

if (score >= 50) {
    console.log("Pass");
} ____ {
    console.log("Fail");
}

Show answer

if (score >= 50) {
    console.log("Pass");
} else {
    console.log("Fail");
}

What is the output when score = 75?
```
if (score >= 90) { console.log("A"); }
else if (score >= 80) { console.log("B"); }
else { console.log("C"); }
```
- A
- C
- B
- 75
Show answer

C — 75 reaches neither 90 nor 80; the else block prints "C".
Match each construct to its job

if (c)

Tests first condition
else if (c)

Tests next condition
else

When none matched
{ }

Code block

Next lesson: switch

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