请简要介绍getWidth和getHeight方法，并给出一个HTML元素中使用这两个方法的示例。要求以markdown格式输出，并包含代码块。
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```markdown
# Introduction to `getWidth` and `getHeight` Methods

The `getWidth` and `getHeight` methods are typically used in programming contexts, particularly with graphical elements or in web development, to retrieve the width and height of an element or object. However, it's important to note that the exact naming and availability of these methods can vary depending on the programming environment or library.

In the context of web development with JavaScript and HTML, you do not directly call methods named `getWidth` or `getHeight`. Instead, you use properties such as `offsetWidth` and `offsetHeight` to get the dimensions of HTML elements.

## Example Usage in HTML

Here’s how you can use `offsetWidth` and `offsetHeight` to achieve similar functionality in an HTML element:

```html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Element Dimensions Example</title>
</head>
<body>

<div id="myDiv" style="width: 200px; height: 100px; background-color: lightblue;"></div>
<button onclick="getElementSize()">Get Element Size</button>

<script>
function getElementSize() {
  var element = document.getElementById("myDiv");
  var width = element.offsetWidth;
  var height = element.offsetHeight;
  alert("Width: " + width + " pixels, Height: " + height + " pixels");
}
</script>

</body>
</html>
```

This example defines a `div` element with a specific width and height and a button that, when clicked, calls the `getElementSize` function. This function retrieves the width and height of the `div` using the `offsetWidth` and `offsetHeight` properties and then displays them in an alert messagebox.
```

```markdown
In this example, `offsetWidth` and `offsetHeight` serve the purpose of getting the dimensions of the HTML element, much like the hypothetical `getWidth` and `getHeight` methods.
```
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