anchor-center-offset-change.html (1119B)
1 <!DOCTYPE html> 2 <title>CSS Anchor Positioning Test: Dynamically change the anchor-center position</title> 3 <link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/#anchor-center"> 4 <script src="/resources/testharness.js"></script> 5 <script src="/resources/testharnessreport.js"></script> 6 <style> 7 #cb { 8 position: relative; 9 width: 200px; 10 height: 200px; 11 } 12 #anchor { 13 width: 100px; 14 height: 100px; 15 anchor-name: --anchor; 16 } 17 #anchored { 18 position: absolute; 19 width: 100px; 20 height: 100px; 21 position-anchor: --anchor; 22 align-self: anchor-center; 23 left: anchor(--unknown right, 0px); 24 } 25 </style> 26 <div id="cb"> 27 <div id="anchor"></div> 28 <div id="anchored"></div> 29 </div> 30 <script> 31 test(() => { 32 assert_equals(anchored.offsetLeft, 0); 33 assert_equals(anchored.offsetTop, 0); 34 }, "Anchored initially have the same width as the anchor"); 35 36 test(() => { 37 anchor.style.height = "200px"; 38 assert_equals(anchored.offsetLeft, 0); 39 assert_equals(anchored.offsetTop, 50); 40 }, "Increase the height of the anchor to move the anchor-center offset"); 41 </script>