<!DOCTYPE html><title>CSS Values and Units Test: attr() security limitations in universal selector </title><linkrel="help"href="https://drafts.csswg.org/css-values-5/#attr-security"><scriptsrc="/resources/testharness.js"></script><scriptsrc="/resources/testharnessreport.js"></script><style>@property--some-string{syntax:"<string>";inherits:true;initial-value:"empty";}*{--some-string:"https://does-not-exist.test/404.png";}div{--some-string:attr(data-foo);background-image:image-set(var(--some-string));}</style><html><body><divid="attr"data-foo="https://does-not-exist.test/404.png"></div></body></html><script>varelem=document.getElementById("attr");test(()=>{assert_equals(window.getComputedStyle(elem).getPropertyValue('background-image'),'none',"'background-image: attr(data-foo)' with data-foo='https://does-not-exist.test/404.png'");});</script>