JavaScript Conditional Statement Examples: Making Decisions in Code

📚 Quick Study Guide

• 🔑 Conditional statements allow you to execute different code blocks based on whether a condition is true or false.
• 💻 The primary conditional statements in JavaScript are if, else if, and else.
• ✅ The if statement executes a block of code if a specified condition is true.

  if (condition) { // code to execute if condition is true }

• 🤔 The else statement executes a block of code if the condition in the if statement is false.

  if (condition) { // code to execute if condition is true } else { // code to execute if condition is false }

• ✨ The else if statement allows you to check multiple conditions in sequence.

  if (condition1) { // code to execute if condition1 is true } else if (condition2) { // code to execute if condition2 is true } else { // code to execute if all conditions are false }

• 🔀 The switch statement is another way to handle multiple conditions, comparing a variable against different cases.

  switch (expression) { case value1: // code to execute if expression === value1 break; case value2: // code to execute if expression === value2 break; default: // code to execute if expression doesn't match any case }

• 💡 Best Practice: Use if/else if/else for conditions based on boolean evaluations or comparisons, and switch for conditions based on specific values.

🧪 Practice Quiz

1. Which statement is used to execute a block of code only if a specified condition is true?
   1. else
   2. if
   3. switch
   4. case
2. What happens if the condition in an if statement is false?
   1. The code inside the if block is executed.
   2. The code inside the else block (if it exists) is executed.
   3. The program throws an error.
   4. Nothing happens.
3. Which statement allows you to check multiple conditions in sequence?
   1. if
   2. else
   3. else if
   4. switch
4. What is the purpose of the default case in a switch statement?
   1. It specifies the condition that must be met.
   2. It executes when none of the other cases match.
   3. It's the first case to be evaluated.
   4. It's not necessary in a switch statement.
5. Which of the following is NOT a valid conditional statement in JavaScript?
   1. if
   2. else
   3. elseif
   4. switch
6. How do you specify multiple conditions within an if statement?
   1. Using commas (,)
   2. Using semicolons (;)
   3. Using logical operators (&&, ||)
   4. By nesting if statements
7. What is the output of the following code?

   let x = 5;
   if (x > 10) {
    console.log("x is greater than 10");
   } else {
    console.log("x is not greater than 10");
   }

   1. x is greater than 10
   2. x is not greater than 10
   3. Error
   4. undefined