| <!DOCTYPE html> |
| <meta charset="utf-8"> |
| <title>CSS Properties and Values: var() references to a property in a font-relative unit cycle</title> |
| <link rel="help" href="https://drafts.css-houdini.org/css-properties-values-api-1/#dependency-cycles"> |
| <link rel="help" href="https://drafts.csswg.org/css-values-5/#cyclic-substitution-contexts"> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| |
| <style> |
| @property --x { |
| syntax: "<length>"; |
| inherits: false; |
| initial-value: 3px; |
| } |
| |
| /* Because --x is a registered custom property using em, it depends on font-size, |
| forming the cycle `font-size -> --y -> --x -> font-size` which invalidates |
| everything in the chain. */ |
| #foo { |
| --x: 3em; |
| --y: var(--x); |
| font-size: var(--y); |
| --zx: var(--x, 5px); |
| --zy: var(--y, 5px); |
| } |
| </style> |
| |
| <div id="foo"></div> |
| |
| <script> |
| test(() => { |
| let style = getComputedStyle(document.getElementById("foo")); |
| assert_equals(style.getPropertyValue("--zx"), "3px"); |
| }, "Registered property invalidated by a non-custom cycle uses its initial value"); |
| |
| test(() => { |
| let style = getComputedStyle(document.getElementById("foo")); |
| assert_equals(style.getPropertyValue("--zy"), "5px"); |
| }, "Unregistered property invalidated by a non-custom cycle uses its fallback"); |
| </script> |
