If you are referring to the id that is found in the regular export in the section to copy to a page surrounding the script tag. That is actually modified once the script executes in place and finds that it is a duplicate. If you look at the elements in your inspector of choice you can actually see the changed ID. The same happens for IDs you assign throughout your document. That is why Hype had to build a "lookup" table for the changes it makes to the ID and arte duplicated (like from layout to layout or scene to scene) and that is why you need to use hypeDocument.getElementById instead of document.getElementById inside of your project code. The Hype version goes through the lookup instead of doing a direct DOM lookup. Apart of that… I am a CSS class person myself. Always prefer them over ID's. 