# Introduction Dropzone is a simple JavaScript library that helps you add file drag and drop functionality to your web forms. It is one of the most popular drag and drop library on the web and is used by millions of people. There are *many* configuration options, so Dropzone can be used in a variety of situations. Some of Dropzone's highlights are: * Beautiful by default. * Image thumbnail previews. Simply register the callback `thumbnail(file, data)` and display the image wherever you like * Progress Bars * Retina enabled * Multiple files and synchronous uploads * Support for large files * Chunked uploads (single files can be uploaded as chunks in multiple HTTP requests) * Complete theming. The look and feel of Dropzone is just the default theme. You can define everything yourself by overwriting the default event listeners. * Browser image resizing (resize the images before you upload them to your server) * Well tested --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.dropzone.dev/undefined.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.