| <!DOCTYPE html> |
| <style> |
| #detector { width: 5px; } |
| @media (-webkit-device-pixel-ratio:1) { #detector { width: 10px; } } |
| @media (-webkit-device-pixel-ratio:3) { #detector { width: 30px; } } |
| @media (-webkit-device-pixel-ratio:4) { #detector { width: 40px; } } |
| </style> |
| <script> |
| function devicePixelRatioFromStyle() { |
| var width = getComputedStyle(document.getElementById("detector")).width; |
| switch (width) { |
| case "10px": |
| return 1; |
| case "30px": |
| return 3; |
| case "40px": |
| return 4; |
| default: |
| return "unknown width: " + width; |
| } |
| } |
| </script> |
| <div id="detector"></div> |
