<!DOCTYPE html> <link rel="help" href="https://drafts.csswg.org/css-scroll-snap-1/#scroll-snap-type" /> <meta name="viewport" content="user-scalable=no"> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <style> html { margin: 0px; overflow: scroll; scroll-snap-type: both mandatory; } div { position: absolute; } .scroller { overflow: scroll; scroll-snap-type: both mandatory; } #inner-scroller { top: 3000px; width: 800px; height: 800px; } .space { left: 0px; top: 0px; width: 4000px; height: 4000px; } .target { width: 600px; height: 600px; scroll-snap-align: start; } .left { left: 0px; } .right { left: 1000px; } .top { top: 0px; } .bottom { top: 1000px; } </style> <body class="scroller"> <div class="space"></div> <div class="target left top"></div> <div class="target right top"></div> <div class="target left bottom"></div> <div class="target right bottom"></div> <div class="scroller" id="inner-scroller"> <div class="space"></div> <div class="target left top"></div> <div class="target right top"></div> <div class="target left bottom"></div> <div class="target right bottom"></div> </div> </body> <script> function format_dict(dict) { const props = []; for (let prop in dict) { props.push(`${prop}: ${format_value(dict[prop])}`); } return `{${props.join(', ')}}`; } var divScroller = document.getElementById("inner-scroller"); var viewport = document.scrollingElement; [ [{left: 800}, 1000, 0], [{top: 900}, 0, 1000], [{left: 900, top: 800}, 1000, 1000], [{left: 800, top: -100}, 1000, 0], /* outside bounds on y axis */ [{left: 10000, top: -100}, 1000, 0] /* outside bounds on both axes */ ].forEach(([input, expectedX, expectedY]) => { test(() => { divScroller.scrollTo(0, 0); assert_equals(divScroller.scrollLeft, 0); assert_equals(divScroller.scrollTop, 0); if (input.left) divScroller.scrollLeft = input.left; if (input.top) divScroller.scrollTop = input.top; assert_equals(divScroller.scrollLeft, expectedX); assert_equals(divScroller.scrollTop, expectedY); }, `assign scrollLeft and scrollTop for ${format_dict(input)} on div lands on (${expectedX}, ${expectedY})`); test(() => { viewport.scrollTo(0, 0); assert_equals(viewport.scrollLeft, 0); assert_equals(viewport.scrollTop, 0); if (input.left) viewport.scrollLeft = input.left; if (input.top) viewport.scrollTop = input.top; assert_equals(viewport.scrollLeft, expectedX); assert_equals(viewport.scrollTop, expectedY); }, `assign scrollLeft and scrollTop for ${format_dict(input)} on viewport-defining element lands on (${expectedX}, ${expectedY})`); test(() => { divScroller.scrollTo(0, 0); assert_equals(divScroller.scrollLeft, 0); assert_equals(divScroller.scrollTop, 0); divScroller.scrollTo(input); assert_equals(divScroller.scrollLeft, expectedX); assert_equals(divScroller.scrollTop, expectedY); }, `scrollTo(${format_dict(input)}) on div lands on (${expectedX}, ${expectedY})`); test(() => { divScroller.scrollTo(0, 0); assert_equals(divScroller.scrollLeft, 0); assert_equals(divScroller.scrollTop, 0); divScroller.scrollBy(input); assert_equals(divScroller.scrollLeft, expectedX); assert_equals(divScroller.scrollTop, expectedY); }, `scrollBy(${format_dict(input)}) on div lands on (${expectedX}, ${expectedY})`); test(() => { viewport.scrollTo(0, 0); assert_equals(viewport.scrollLeft, 0); assert_equals(viewport.scrollTop, 0); viewport.scrollTo(input); assert_equals(viewport.scrollLeft, expectedX); assert_equals(viewport.scrollTop, expectedY); }, `scrollTo(${format_dict(input)}) on viewport-defining element lands on (${expectedX}, ${expectedY})`); test(() => { viewport.scrollTo(0, 0); assert_equals(viewport.scrollLeft, 0); assert_equals(viewport.scrollTop, 0); viewport.scrollBy(input); assert_equals(viewport.scrollLeft, expectedX); assert_equals(viewport.scrollTop, expectedY); }, `scrollBy(${format_dict(input)}) on viewport-defining element lands on (${expectedX}, ${expectedY})`); test(() => { window.scrollTo(0, 0); assert_equals(window.scrollX, 0); assert_equals(window.scrollY, 0); window.scrollTo(input); assert_equals(window.scrollX, expectedX); assert_equals(window.scrollY, expectedY); }, `scrollTo(${format_dict(input)}) on window lands on (${expectedX}, ${expectedY})`); test(() => { window.scrollTo(0, 0); assert_equals(window.scrollX, 0); assert_equals(window.scrollY, 0); window.scrollBy(input); assert_equals(window.scrollX, expectedX); assert_equals(window.scrollY, expectedY); }, `scrollBy(${format_dict(input)}) on window lands on (${expectedX}, ${expectedY})`); }); </script>