Window.devicePixelRatio

- WD

Read-only property that returns the ratio of the (vertical) size of one physical pixel on the current display device to the size of one CSS pixel.

Chrome

  1. 4 - 124: Supported
  2. 125: Supported
  3. 126 - 128: Supported

Edge

  1. 12 - 124: Supported
  2. 125: Supported

Safari

  1. 3.1 - 17.4: Supported
  2. 17.5: Supported
  3. 17.6 - TP: Supported

Firefox

  1. 2 - 17: Not supported
  2. 18 - 125: Supported
  3. 126: Supported
  4. 127 - 129: Supported

Opera

  1. 9 - 11.5: Not supported
  2. 11.6 - 108: Supported
  3. 109: Supported

IE

  1. 5.5 - 10: Not supported
  2. 11: Supported

Chrome for Android

  1. 124: Supported

Safari on iOS

  1. 3.2 - 17.4: Supported
  2. 17.5: Supported
  3. 17.6: Supported

Samsung Internet

  1. 4 - 23: Supported
  2. 24: Supported

Opera Mini

  1. all: Supported

Opera Mobile

  1. 10 - 11.5: Not supported
  2. 12 - 12.1: Supported
  3. 80: Supported

UC Browser for Android

  1. 15.5: Supported

Android Browser

  1. 2.1 - 4.4.4: Supported
  2. 124: Supported

Firefox for Android

  1. 125: Supported

QQ Browser

  1. 14.9: Supported

Baidu Browser

  1. 13.52: Supported

KaiOS Browser

  1. 2.5: Supported
  2. 3: Supported

As the page is zoomed in the number of device pixels that one CSS pixel covers increases, and therefore the value of devicePixelRatio will also increase.

Resources:
MDN Web Docs - devicePixelRatio