What is Progressive Enhancement?

The idea of layering content within semantic markup (HTML) first, then CSS styles next, then JavaScript next, so that each layer can be peeled off by devices that don’t support it without affecting layers beneath, is called Progressive Enhancement. It sums up the general best-practice web development strategy for how to manage the relationship of these technologies.

One of the possible further layers on top, even more advanced than JavaScript, is jquery (a framework for JavaScript). The main thing to consider is to ensure jquery within a webpage does not destroy the site’s usability, which is termed as ‘non conflicting jquery’. There is a trend in jquery to use shortcut lines of code beginning with a $ sign like $(), which is short for typing jQuery(), and this frequently causes errors where other scripting libraries try to also use the popular $ sign at the start of each line of code. Technically this isn’t so much an SEO issue but if we’re doing from the bottom-most levels to the top, then jqeury is a suitable thing to put at the top of the layers and non-conflicting is the recommended ‘type’ of jquery.