If–else statement in Javascript - Step-by-Step Execution

Concept Flow - If–else statement

Start

↓

Evaluate condition

↓

Execute 'if' block

↓

End

↓

Execute 'else' block

↓

End

The program checks a condition. If true, it runs the 'if' block; otherwise, it runs the 'else' block.

Execution Sample

Javascript

let age = 18;
if (age >= 18) {
  console.log('Adult');
} else {
  console.log('Minor');
}

This code checks if age is 18 or more and prints 'Adult' if true, otherwise 'Minor'.

Execution Table

Step	Condition (age >= 18)	Result	Branch Taken	Output
1	18 >= 18	true	if block	Adult
2	N/A	N/A	End	Program ends

💡 Condition is true at step 1, so 'if' block runs and program ends after.

Variable Tracker

Variable	Start	After Step 1	Final
age	18	18	18

Key Moments - 2 Insights

Why does the program print 'Adult' and not 'Minor'?

Because at step 1 in the execution table, the condition 'age >= 18' is true, so the 'if' block runs and the 'else' block is skipped.

What happens if the condition is false?

If the condition was false, the program would run the 'else' block instead, as shown by the branch taken in the execution table.

Visual Quiz - 3 Questions

Look at the execution table, what is the output at step 1?

A Error

B Adult

C Minor

D No output

💡 Hint

Check the 'Output' column at step 1 in the execution table.

At which step does the program decide which block to run?

A Step 2

B Before Step 1

C Step 1

D After Step 2

💡 Hint

Look at the 'Condition' and 'Branch Taken' columns in the execution table.

If age was 16, what would the output be according to the tables?

A Minor

B Adult

C No output

D Error

💡 Hint

Think about the condition 'age >= 18' and which branch runs when false.

Concept Snapshot

if (condition) {
  // code runs if condition true
} else {
  // code runs if condition false
}
Checks condition once, runs one block only.

Full Transcript

This visual execution shows how an if-else statement works in JavaScript. The program starts by checking the condition 'age >= 18'. If true, it runs the code inside the 'if' block and prints 'Adult'. If false, it runs the 'else' block and prints 'Minor'. The execution table traces each step, showing the condition result, which branch runs, and the output. The variable tracker shows the value of 'age' stays the same. Key moments clarify why the program chooses one block over the other. The quiz tests understanding by asking about outputs and decision steps.