JavaScript If Else

What is Control Flow?

JavaScript Control Flow refers to the way in which the execution of code progresses through a script. Control flow determines the order in which statements are executed, depending on conditions, loops, or other constructs.

JavaScript If Else

In JavaScript, the if...else statement allows you to execute certain blocks of code based on a condition. If the condition evaluates to true, the code inside the if block will execute. If the condition evaluates to false, the code inside the else block will execute (if present).

In JavaScript, the if...else statement allows you to execute certain blocks of code based on a condition. If the condition evaluates to true, the code inside the if block will execute. If the condition evaluates to false, the code inside the else block will execute (if present).

Syntax:

  if (condition) {
    // Code to run if the condition is true
  } else {
      // Code to run if the condition is false
  }

Example:

Here’s a simple example:

  let age = 18;
  if (age >= 18) {
      console.log("You are eligible to vote.");
  } else {
      console.log("You are not eligible to vote.");
  }

Explanation:

• The variable age is set to 18.
• The if statement checks whether the condition age >= 18 is true.
  • If true, the message "You are eligible to vote." is displayed.
  • If false, the else block runs and displays "You are not eligible to vote."

Output:

You are eligible to vote.

Example with else if:

You can also nest multiple if...else statements or use else if for multiple conditions.

  let score = 85;
  if (score >= 90) {
      console.log("Grade: A");
  } else if (score >= 80) {
      console.log("Grade: B");
  } else if (score >= 70) {
      console.log("Grade: C");
  } else {
      console.log("Grade: F");
  }

Explanation:

• If the score is 90 or higher, the output will be "Grade: A".
• If the score is between 80 and 89, the output will be "Grade: B".
• If the score is between 70 and 79, the output will be "Grade: C".
• For any other score, the output will be "Grade: F".

This flexibility allows you to handle a variety of conditions in your program.