<!doctype html> <html> <head> <link rel="help" href="https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-setproperty"/> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> </head> <body> <script> var style = document.body.style; test(function() { style.color = 'white'; assert_equals(style.color, 'white'); style.setProperty('color', undefined); assert_equals(style.color, 'white'); }, "Verify that setting a CSS property to undefined has no effect."); test(function() { style.color = 'white'; assert_equals(style.color, 'white'); assert_equals(style.getPropertyPriority('color'), ''); style.setProperty('color', 'red', undefined); assert_equals(style.color, 'red'); assert_equals(style.getPropertyPriority('color'), ''); }, "Verify that setting a CSS property priority to undefined is accepted."); test(function() { style.color = 'white'; assert_equals(style.color, 'white'); style.setProperty('color', null); assert_equals(style.color, ''); }, "Verify that setting a CSS property to null is treated like empty string."); test(function() { style.color = 'white'; assert_equals(style.color, 'white'); style.setProperty('color', 'red', null); assert_equals(style.color, 'red'); }, "Verify that setting a CSS property priority to null is treated like empty string."); </script> </body> </html>