Browsers specific behaviour


Covered in this doc

  • Handling of Alerts
  • Files Auto download
  • Handling filter property
  • Very large page in Firefox

This document describes various issues related to different browsers and how they handle specific scenarios like Alerts and Auto downloading of video files etc.

Safari on iPhone & Mac

While doing visual regression testing with Percy, If your webpage is having javascript based alerts or video files getting automatically downloaded on opening the webpage, in that scenario you might see builds getting failed.

Primary reason is that these alerts and auto downloading of video files do not work well with various testing frameworks like Selenium or Appium today.

Safari on iPhone

If your webpage is using CSS property filter very often or having too many references, then it may break. This is only observed during Safari on iPhone and in future this may work when Apple fixes it, until then use the CSS filter property carefully.


In Firefox we observed, when webpage is too large that full-page screenshot total size may go beyond 32k pixels, then it may break, which may result in missing/failed snapshot.

You can try on your local environment using Firefox built in mechanism, more information here. Also please checkout Browsers specific handling doc for more information.