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Accessibility
Why do shake and tilt functions need an alternative?
Functions triggered by shaking, tilting, or leaning the device need an alternative through ordinary control elements — and a way to turn them off. People with tremors shake their phone unintentionally and trigger the function without meaning to; people with a device mounted in a fixed position, for example on a wheelchair, can't move it at all. WCAG criterion 2.5.4 "Motion Actuation" covers both cases.
Shake to undo, and other motion functions
Motion control sounds modern and is common in apps: shaking undoes the last input, tilting scrolls forward, leaning steers a game. Websites too can offer such functions via a phone's motion sensors. The criterion requires two things. First, equivalent operation through visible elements: alongside "shake to undo" there must also be an undo button. Second, a way to turn off motion triggering — for anyone whose hands tremble and who would otherwise keep undoing things unintentionally. The only exception is anything that measures the motion itself, such as a step counter. The most honest question to ask beforehand is: does the website need motion control at all.
How the audit service reports this criterion
Whether a website responds to device motion could only be established by having the check trigger motion events and observe the consequences — an intervention our passive measurement engine deliberately avoids: it triggers no functions on your website. An automatic judgment would therefore not be backed by any measurement. The audit report instead openly marks the criterion as a point for manual review. Since motion-controlled functions are rare on ordinary business websites, this human review is usually quick — but it still belongs in the report, so the seal's claim remains fully supported.
- Ask your agency whether your website or app responds to shaking, tilting, or leaning.
- Give every motion function a visible control element with the same effect alongside it.
- Offer a setting that lets motion triggering be turned off completely.
- When in doubt, skip motion control — a button serves the same purpose for everyone.
FAQ
What is motion actuation on websites and apps?
Motion actuation means a function is triggered by moving the device — shaking undoes, tilting scrolls, leaning steers. Phones report such movements to websites too, via built-in sensors. WCAG requires a visible control element with the same effect for every such function, plus a way to turn off motion triggering.
For whom is motion control an obstacle?
For two groups at once: people with tremors or spasms move their device unintentionally and trigger the function without meaning to — right in the middle of typing, an undo suddenly happens. People with a device mounted in a fixed position, for example on a wheelchair, can't perform the required motion at all. Without an alternative, the function stays completely out of reach for them.
Does the criterion also apply to ordinary business websites?
Mostly only marginally: motion-controlled functions are rare on classic business websites and tend to be found in apps and games instead. It's still worth checking, however, especially with embedded third-party components. Our audit report therefore lists the criterion as a manual check point — on a website with no motion functions it's answered quickly, but it's never silently skipped.