JavaScript Code for Selecting and Appending Elements

// Select an HTML element by its ID
var outputElement = document.getElementById("output");

// Create a new paragraph element
var paragraph = document.createElement("p");

// Set the text content of the paragraph
paragraph.textContent = "Hello, World!";

// Append the paragraph to the selected element
outputElement.appendChild(paragraph);

The provided code snippet is written in JavaScript.

To fix the syntax errors:

// Select an HTML element by its ID
var outputElement = document.getElementById("output");

// Create a new paragraph element
var paragraph = document.createElement("p");

// Set the text content of the paragraph
paragraph.textContent = "Hello, World!";

// Append the paragraph to the selected element
outputElement.appendChild(paragraph);

The original code doesn't have any syntax errors, so no changes were needed. The code selects an HTML element with the ID "output", creates a new paragraph element, sets the text content of the paragraph to "Hello, World!", and appends the paragraph to the selected element.