Through JavaScript, you can refactor the entire HTML document. You can add, remove, change, or rearrange items on the page. (For example, you can use JavaScript to move a website's sidebar to customize it.) Simply put, the DOM is the interface that allows you to interact with the webpage.
The full name of DOM is Document Object Model (文档对象模型). So, what is the DOM used for? If you consider your document as a single object, the DOM is the standard for how to manipulate and control this object using HTML or XML.