Asynchronous JavaScript
The async attribute on the poll unit integration code <script> element instructs the browser to load the poll unit JavaScript library asynchronously without pausing the rendering of the page while the script is downloaded. JSONP requests during the poll unit life-cycle are also asynchronous.
Caching
To facilitate rapid deployment of bug fixes and new features without requiring our partners to adjust the poll unit integration code, requests for the poll unit JavaScript require a trip to our server. However, our server is configured to respond with 304 Not Modified when possible, saving the bandwidth that would otherwise have been required to download the entire library.