| <!doctype html> |
| <html> |
| <head> |
| <meta charset=utf-8> |
| <title>CSS Transitions Test: behavior when transition-duration changes while transitioning</title> |
| <meta name="assert" content="Checks a change to the transition-duration |
| property does not affect an in-flight transition"> |
| <link rel="help" title="3. Starting of transitions" href="https://drafts.csswg.org/css-transitions/#starting"> |
| |
| <script src="/resources/testharness.js" type="text/javascript"></script> |
| <script src="/resources/testharnessreport.js" type="text/javascript"></script> |
| <script src="./support/helper.js" type="text/javascript"></script> |
| |
| </head> |
| <body> |
| <div id="log"></div> |
| |
| <script> |
| promise_test(async t => { |
| // Start a 100s transition 50% of the way through |
| const div = addDiv(t, { |
| style: 'transition: height 100s -50s linear; height: 0px', |
| }); |
| getComputedStyle(div).height; |
| div.style.height = '100px'; |
| assert_equals( |
| getComputedStyle(div).height, |
| '50px', |
| 'Transition should be initially 50% complete' |
| ); |
| |
| // Extend the transition-duration to 200s. |
| div.style.transitionDuration = '200s'; |
| |
| // If the change to the transition-duration was reflected, the |
| // computed height would now be '25px'. |
| assert_equals( |
| getComputedStyle(div).height, |
| '50px', |
| 'Even after updating the transition-duration, the transition should be 50% complete' |
| ); |
| |
| // Wait a frame just to be sure that the changed duration is not later |
| // updated. |
| await waitForFrame(); |
| |
| assert_greater_than_equal( |
| parseInt(getComputedStyle(div).height), |
| 50, |
| 'Even in the next frame the updated transition-duration should not apply' |
| ); |
| }, 'Changes to transition-duration should not affect in-flight transitions'); |
| </script> |
| |
| </body> |
| </html> |
