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Exercise 22: Counting Vowels in a String with JavaScript

Discover how to count vowels in a string using JavaScript. This exercise is ideal for practicing iterations and regular expressions. The main purpose is to practice using them.forand conditionals to analyze the content of a string, counting the vowels.

Activity​

  1. Ask the user to enter a word or phrase.

  2. Use a loopforto iterate through each character of the entered string.

  3. Check if the current character is a vowel (a,e,i,o,u(in lowercase or uppercase).

  4. If it is a vowel, increment a counter.

  5. At the end of the loop, display the total number of vowels found in the console.

Solution​

Step 1: Create the index.html file​

HTML
<!DOCTYPE html>
<html lang="es">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Contar vocales en una cadena</title>
  </head>
  <body>
    <h1>Ejercicio 22: Contar vocales en una cadena</h1>
    <p>Los cambios se muestran en consola.</p>
    <script src="script.js"></script>
  </body>
</html>

Step 2: Write the code in script.js​

JavaScript
let texto = prompt("Ingresa una palabra o frase:");
let contadorVocales = 0;

for (let i = 0; i < texto.length; i++) {
  let caracter = texto[i].toLowerCase();
  if (
    caracter === "a" ||
    caracter === "e" ||
    caracter === "i" ||
    caracter === "o" ||
    caracter === "u"
  ) {
    contadorVocales++;
  }
}

console.log(`La cantidad de vocales en "${texto}" es: ${contadorVocales}`);
info

🔎Check the sectionControl instructions in JavaScriptwhere you will find more information on this topic.