You can create an accordion using HTML, CSS, and JavaScript. Here is an example code for creating an accordion:

HTML Code:

html
 
 
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<div class="accordion">
  <div class="accordion-item">
    <div class="accordion-header">
      Item 1
      <span class="icon">&#x25B6;</span>
    </div>
    <div class="accordion-content">
      Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse accumsan neque condimentum leo interdum, et gravida orci porttitor. 
    </div>
  </div>
  <div class="accordion-item">
    <div class="accordion-header">
      Item 2
      <span class="icon">&#x25B6;</span>
    </div>
    <div class="accordion-content">
      Aliquam erat volutpat. In a odio eu lacus varius malesuada. Nulla eu facilisis felis. Integer eu magna vel risus tincidunt aliquet. 
    </div>
  </div>
  <div class="accordion-item">
    <div class="accordion-header">
      Item 3
      <span class="icon">&#x25B6;</span>
    </div>
    <div class="accordion-content">
      Curabitur varius magna in mauris mattis, ut sagittis orci sagittis. In vitae elementum tellus. Fusce sed venenatis ipsum, in congue quam. 
    </div>
  </div>
</div>

CSS Code:

css
 
 
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.accordion {
  width: 100%;
}

.accordion-item {
  background-color: #fff;
  margin-bottom: 10px;
  padding: 10px;
  border: 1px solid #ccc;
}

.accordion-header {
  font-size: 18px;
  font-weight: bold;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.accordion-content {
  display: none;
  padding: 10px;
}

.icon {
  font-size: 20px;
  margin-left: auto;
  transform: rotate(90deg);
  transition: all 0.2s ease;
}

.open .icon {
  transform: rotate(0);
}

JavaScript Code:

javascript
 
 
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const accordionItems = document.querySelectorAll(".accordion-item");

accordionItems.forEach(item =>
  item.addEventListener("click", () => {
    const isItemOpen = item.classList.contains("open");
    accordionItems.forEach(item => item.classList.remove("open"));
    if (!isItemOpen) {
      item.classList.toggle("open");
    }
  })
);

Explanation:

1. The first step is to create a container div with a class of 'accordion'.
2. Add an accordion item div for each item in the accordion.
3. Each accordion item consists of a header and content.
4. The header contains text and a span element with a class of 'icon'.
5. The 'icon' class contains an arrow symbol that is rotated when the accordion item is clicked.
6. The content is hidden by default.
7. The CSS styles for the accordion and its contents are defined in the styles.
8. The JavaScript code adds a click event listener to each accordion item.
9. When an accordion item is clicked, the script checks if it is already open.
10. If the accordion item is open, the script removes the 'open' class.
11. If the accordion item is closed, the script toggles the 'open' class, which opens its content.

A function is a block of organized, reusable code that is used to perform a single, related action. Functions provide better modularity for your application and a high degree of code reusing. In JavaScript, functions are first-class objects, because they can have properties and methods just like any other object. There are several ways to create a function:

• Function Declaration
• Function Expression
• Arrow Functions
• Function Constructors

Below is an example of a function declaration in JavaScript:

javascript
 
 
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// example of a function declaration
function sayHello(){
  console.log('Hello!');
}

// call the function
sayHello();

This is an example of what the output looks like when this code is run:

code
 
 
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Hello!