| <!DOCTYPE html> | 
 | <title>CSS Anchor Positioning: basic position-area positioning</title> | 
 | <link rel="help" href="https://drafts.csswg.org/css-anchor-position/#position-area"> | 
 | <script src="/resources/testharness.js"></script> | 
 | <script src="/resources/testharnessreport.js"></script> | 
 | <!-- The grid: | 
 |  | 
 |           100      150      150 | 
 |       +--------+--------+--------+ | 
 |       |        |        |        | | 
 |   150 |        |        |        | | 
 |       |        |        |        | | 
 |       +--------+--------+--------+ | 
 |       |        |        |        | | 
 |    75 |        |        |        | | 
 |       |        |        |        | | 
 |       +--------+--------+--------+ | 
 |       |        |        |        | | 
 |   175 |        |        |        | | 
 |       |        |        |        | | 
 |       +--------+--------+--------+ | 
 |  | 
 |   --> | 
 | <style> | 
 |   #container { | 
 |     position: absolute; | 
 |     width: 400px; | 
 |     height: 400px; | 
 |     margin: 0 auto; | 
 |     border: 2px solid; | 
 |     background: #eee; | 
 |   } | 
 |   #anchored { | 
 |     position: absolute; | 
 |     align-self: stretch; | 
 |     justify-self: stretch; | 
 |     position-anchor: --anchor; | 
 |     background: #FA08; | 
 |     outline: 1px solid orange; | 
 |   } | 
 |   #anchor { | 
 |     margin-top: 150px; | 
 |     margin-left: 100px; | 
 |     width: 150px; | 
 |     height: 75px; | 
 |     anchor-name: --anchor; | 
 |     background: blue; | 
 |   } | 
 | </style> | 
 | <div id="container"> | 
 |   <div id="anchored"></div> | 
 |   <div id="anchor"></div> | 
 | </div> | 
 | <script> | 
 |   function test_position_area(position_area, expected_offsets) { | 
 |     anchored.style.positionArea = position_area; | 
 |     test(() => { | 
 |       assert_equals(anchored.offsetLeft, expected_offsets.left, "Check expected offsetLeft"); | 
 |       assert_equals(anchored.offsetTop, expected_offsets.top, "Check expected offsetTop"); | 
 |       assert_equals(anchored.offsetWidth, expected_offsets.width, "Check expected offsetWidth"); | 
 |       assert_equals(anchored.offsetHeight, expected_offsets.height, "Check expected offsetHeight"); | 
 |     }, "Offsets for: " + position_area); | 
 |   } | 
 |  | 
 |   test_position_area("none", {left:0, top:0, width:0, height:0}); | 
 |   test_position_area("span-all", {left:0, top:0, width:400, height:400}); | 
 |   test_position_area("span-all span-all", {left:0, top:0, width:400, height:400}); | 
 |  | 
 |   // Single region spans | 
 |   test_position_area("top left", {left:0, top:0, width:100, height:150}); | 
 |   test_position_area("top center", {left:100, top:0, width:150, height:150}); | 
 |   test_position_area("top right", {left:250, top:0, width:150, height:150}); | 
 |   test_position_area("center left", {left:0, top:150, width:100, height:75}); | 
 |   test_position_area("center center", {left:100, top:150, width:150, height:75}); | 
 |   test_position_area("center right", {left:250, top:150, width:150, height:75}); | 
 |   test_position_area("bottom left", {left:0, top:225, width:100, height:175}); | 
 |   test_position_area("bottom center", {left:100, top:225, width:150, height:175}); | 
 |   test_position_area("bottom right", {left:250, top:225, width:150, height:175}); | 
 |  | 
 |   test_position_area("start start", {left:0, top:0, width:100, height:150}); | 
 |   test_position_area("start center", {left:100, top:0, width:150, height:150}); | 
 |   test_position_area("start end", {left:250, top:0, width:150, height:150}); | 
 |   test_position_area("center start", {left:0, top:150, width:100, height:75}); | 
 |   test_position_area("center end", {left:250, top:150, width:150, height:75}); | 
 |   test_position_area("end start", {left:0, top:225, width:100, height:175}); | 
 |   test_position_area("end center", {left:100, top:225, width:150, height:175}); | 
 |   test_position_area("end end", {left:250, top:225, width:150, height:175}); | 
 |  | 
 |   test_position_area("self-start self-start", {left:0, top:0, width:100, height:150}); | 
 |   test_position_area("self-start center", {left:100, top:0, width:150, height:150}); | 
 |   test_position_area("self-start self-end", {left:250, top:0, width:150, height:150}); | 
 |   test_position_area("center self-start", {left:0, top:150, width:100, height:75}); | 
 |   test_position_area("center self-end", {left:250, top:150, width:150, height:75}); | 
 |   test_position_area("self-end self-start", {left:0, top:225, width:100, height:175}); | 
 |   test_position_area("self-end center", {left:100, top:225, width:150, height:175}); | 
 |   test_position_area("self-end self-end", {left:250, top:225, width:150, height:175}); | 
 |  | 
 |   test_position_area("y-start x-start", {left:0, top:0, width:100, height:150}); | 
 |   test_position_area("y-start center", {left:100, top:0, width:150, height:150}); | 
 |   test_position_area("y-start x-end", {left:250, top:0, width:150, height:150}); | 
 |   test_position_area("center x-start", {left:0, top:150, width:100, height:75}); | 
 |   test_position_area("center x-end", {left:250, top:150, width:150, height:75}); | 
 |   test_position_area("y-end x-start", {left:0, top:225, width:100, height:175}); | 
 |   test_position_area("y-end center", {left:100, top:225, width:150, height:175}); | 
 |   test_position_area("y-end x-end", {left:250, top:225, width:150, height:175}); | 
 |  | 
 |   test_position_area("self-y-start self-x-start", {left:0, top:0, width:100, height:150}); | 
 |   test_position_area("self-y-start center", {left:100, top:0, width:150, height:150}); | 
 |   test_position_area("self-y-start self-x-end", {left:250, top:0, width:150, height:150}); | 
 |   test_position_area("center self-x-start", {left:0, top:150, width:100, height:75}); | 
 |   test_position_area("center self-x-end", {left:250, top:150, width:150, height:75}); | 
 |   test_position_area("self-y-end self-x-start", {left:0, top:225, width:100, height:175}); | 
 |   test_position_area("self-y-end center", {left:100, top:225, width:150, height:175}); | 
 |   test_position_area("self-y-end self-x-end", {left:250, top:225, width:150, height:175}); | 
 |  | 
 |   // Multi-region spans | 
 |   test_position_area("span-self-y-start span-self-x-end", {left:100, top:0, width:300, height:225}); | 
 |   test_position_area("span-bottom span-all", {left:0, top:150, width:400, height:250}); | 
 |  | 
 |   // No implicit anchor means the position-area should not apply. | 
 |   anchored.style.positionAnchor = "auto"; | 
 |   test_position_area("span-all top", {left:0, top:0, width:0, height:0}); | 
 | </script> |