Stripping out CSS might sound a bit obscure if you don’t design or develop webpages, but it’s straightforward. HTML defines the bones of a page, like the girders of a skyscraper, and contains the innards—text and images and other stuff—just like an office contains workers and furniture and printers. CSS is the glass and metal panels covering the skyscraper, while also painting the outside and creating the walls and cubicle barriers: It defines how things appear, including the dimensions and placement of both fixed layout areas and boxes that can seemingly float above the page.
iOS 9 lets you select one or more installed blockers to use with Safari.
A CSS “selector” defines the scope of what style definitions apply to. They can be used to attach to an HTML element, reused for multiple parts of a page, or define a specific structure, which is used for those floating boxes among many other purposes. By allowing a blocking filter to strip out specific selectors, it can suppress advertising overlays or other annoying or intrusive behavior.
Apple allows any combination of content-blocking extensions to be enabled at once via Settings > Safari > Content Blockers. And you can override all content filters by holding down the reload button for a few seconds. Instead of a simple reload, it becomes a “reload without filtering.”
How the filters will work in practice
Hold down the reload button in iOS 9 with content-blocking filters enabled to get an unfiltered page.
Content blockers have to be packaged inside of apps, though the apps themselves can be exceedingly simple. In testing just three extensions, I’ve already seen a lot of variety. When we get to the release stage for iOS 9, I expect a huge ecosystem of filter apps, some more sophisticated and configurable than others.
Some will be simple. At this stage of development, Crystal is just a holding place for rules set up by the developer. Adamant has a couple of settings. Blockr has a full configuration screen with three kinds of blocking types, and the ability to whitelist in the app portion. We’ll definitely see a lot of baroque options over time. If Ghostery winds up implemented as an extension, it wouldn’t be able to show its pop-up display, but could offer all its intricate and per-network choices on the app side.
There will definitely be a market for apps that focus on blacklisting and whitelisting. The former is easier, because it’s a subset of everything on the internet, and developers will carve out area like anti-phishing and anti-malware, which will be a great thing to install for relatives and friends who don’t care about technology, but want to browse safely.
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