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wpt / css / css-masking / animations / mask-border-width-composition.html

Spec: CSS Masking ↗

Runs: Chrome 155.0.8041.0 (wpt@4a01b83e3, 2026-09-04) | Firefox 157.0a1 (wpt@e7122b73f, 2026-09-04) | Safari 251 preview (wpt@2c385f65e, 2026-09-04) | Ladybird 1.0-70fb3 (wpt@4a01b83e3, 2026-09-04) | Servo Servo 0.6 (wpt@7e3d005d7, 2026-09-03) | Blitz a50cb8971 (wpt@a95401e4e, 2026-09-03)

View on the Blitz WPT dashboard | Open test on wpt.live | wpt.fyi

ChromeFirefoxSafariLadybirdServoBlitz
Total0/1120/112112/1120/1120/1120/112
SubtestChromeFirefoxSafariLadybirdServoBlitz
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (-0.25) should be [0]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (0) should be [2 4 6 8]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (0.25) should be [27 29 31 33]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (0.5) should be [52 54 56 58]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (0.75) should be [77 79 81 83]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (1) should be [102 104 106 108]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (1.25) should be [127 129 131 133]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (-0.25) should be [0]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (0) should be [2 4 6 8]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (0.25) should be [27 29 31 33]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (0.5) should be [52 54 56 58]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (0.75) should be [77 79 81 83]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (1) should be [102 104 106 108]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3 4] from add [1 2 3 4] to add [101 102 103 104] at (1.25) should be [127 129 131 133]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (-0.25) should be [175 250 300 450]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (0) should be [200 300 400 500]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (0.25) should be [225 350 500 550]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (0.5) should be [250 400 600 600]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (0.75) should be [275 450 700 650]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (1) should be [300 500 800 700]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (1.25) should be [325 550 900 750]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (-0.25) should be [175 250 300 450]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (0) should be [200 300 400 500]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (0.25) should be [225 350 500 550]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (0.5) should be [250 400 600 600]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (0.75) should be [275 450 700 650]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (1) should be [300 500 800 700]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [100 200 300 400] from add [100] to add [200 300 500] at (1.25) should be [325 550 900 750]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (-0.25) should be [0 0 0px 0%]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (0) should be [2 4 6px 8%]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (0.25) should be [27 29 31px 33%]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (0.5) should be [52 54 56px 58%]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (0.75) should be [77 79 81px 83%]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (1) should be [102 104 106px 108%]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (1.25) should be [127 129 131px 133%]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (-0.25) should be [0 0 0px 0%]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (0) should be [2 4 6px 8%]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (0.25) should be [27 29 31px 33%]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (0.5) should be [52 54 56px 58%]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (0.75) should be [77 79 81px 83%]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (1) should be [102 104 106px 108%]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [1 2 3px 4%] from add [1 2 3px 4%] to add [101 102 103px 104%] at (1.25) should be [127 129 131px 133%]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (-0.25) should be [225px 225px 350px 350px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (0) should be [200px 200px 300px 300px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (0.25) should be [175px 175px 250px 250px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (0.5) should be [150px 150px 200px 200px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (0.75) should be [125px 125px 150px 150px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (1) should be [100px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (1.25) should be [75px 75px 50px 50px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (-0.25) should be [225px 225px 350px 350px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (0) should be [200px 200px 300px 300px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (0.25) should be [175px 175px 250px 250px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (0.5) should be [150px 150px 200px 200px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (0.75) should be [125px 125px 150px 150px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (1) should be [100px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20px] from add [190px 180px 290px 280px] to add [90px 80px] at (1.25) should be [75px 75px 50px 50px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (-0.25) should be [75 75px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (0) should be [100 100px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (0.25) should be [125 125px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (0.5) should be [150 150px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (0.75) should be [175 175px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (1) should be [200 200px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (1.25) should be [225 225px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (-0.25) should be [75 75px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (0) should be [100 100px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (0.25) should be [125 125px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (0.5) should be [150 150px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (0.75) should be [175 175px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (1) should be [200 200px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20px] from replace [100 100px] to add [190 180px] at (1.25) should be [225 225px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (-0.25) should be [125px 125]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (0) should be [100px 100]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (0.25) should be [75px 75]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (0.5) should be [50px 50]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (0.75) should be [25px 25]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (1) should be [0px 0]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (1.25) should be [0px 0]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (-0.25) should be [125px 125]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (0) should be [100px 100]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (0.25) should be [75px 75]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (0.5) should be [50px 50]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (0.75) should be [25px 25]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (1) should be [0px 0]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10px 20] from add [90px 80] to replace [0px 0 0px 0] at (1.25) should be [0px 0]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (-0.25) should be [75px 125px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (0) should be [100px 150px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (0.25) should be [125px 175px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (0.5) should be [150px 200px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (0.75) should be [175px 225px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (1) should be [200px 250px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (1.25) should be [225px 275px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (-0.25) should be [75px 125px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (0) should be [100px 150px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (0.25) should be [125px 175px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (0.5) should be [150px 200px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (0.75) should be [175px 225px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (1) should be [200px 250px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100px 150px] to add [200px 250px] at (1.25) should be [225px 275px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (-0.25) should be [100 150px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (0) should be [100 150px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (0.25) should be [100 150px]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (0.5) should be [200% 250]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (0.75) should be [200% 250]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (1) should be [200% 250]FAILFAILPASSFAILFAILFAIL
Compositing CSS Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (1.25) should be [200% 250]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (-0.25) should be [100 150px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (0) should be [100 150px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (0.25) should be [100 150px]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (0.5) should be [200% 250]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (0.75) should be [200% 250]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (1) should be [200% 250]FAILFAILPASSFAILFAILFAIL
Compositing Web Animations: property <mask-border-width> underlying [10 20] from add [100 150px] to add [200% 250] at (1.25) should be [200% 250]FAILFAILPASSFAILFAILFAIL