The includes() method is a built-in function in JavaScript that allows you to check if a string contains another specified string. It returns true if the string contains the specified substring, and false otherwise. Here's the syntax of the includes() method: string.includes(searchString, position) searchString: The substring that you want to check for in the main string. position (optional): The index at which to begin searching for the substring within the main string. If not specified, the default is 0.