Test that changing an empty rule with CSSOM updates the elements correctly. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". Before changing the rules PASS window.getComputedStyle(document.getElementById("target1")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target2")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target3")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target4")).backgroundColor is "rgb(1, 2, 3)" Changing the first-child rule PASS window.getComputedStyle(document.getElementById("target1")).backgroundColor is "rgb(4, 5, 6)" PASS window.getComputedStyle(document.getElementById("target2")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target3")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target4")).backgroundColor is "rgb(1, 2, 3)" Changing the last-child rule PASS window.getComputedStyle(document.getElementById("target1")).backgroundColor is "rgb(4, 5, 6)" PASS window.getComputedStyle(document.getElementById("target2")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target3")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target4")).backgroundColor is "rgb(7, 8, 9)" Emptying the first-child rule PASS window.getComputedStyle(document.getElementById("target1")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target2")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target3")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target4")).backgroundColor is "rgb(7, 8, 9)" Emptying the last-child rule PASS window.getComputedStyle(document.getElementById("target1")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target2")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target3")).backgroundColor is "rgb(1, 2, 3)" PASS window.getComputedStyle(document.getElementById("target4")).backgroundColor is "rgb(1, 2, 3)" PASS successfullyParsed is true TEST COMPLETE