22192 2013-05-29 05:45:31 +0000 [Custom]: Perhaps element's last completion value should not be from an exceptional termination? 2013-05-29 21:06:06 +0000 1 1 1 Unclassified WebAppsWG HISTORICAL - Component Model unspecified PC Linux RESOLVED FIXED P2 normal --- 18719 1 dominicc dglazkov public-webapps-bugzilla oldest_to_newest 88363 0 dominicc 2013-05-29 05:45:31 +0000 "Let PROPERTIES be DOCUMENT's last completion value" I think 'throw' establishes a completion value, so for example this: <element name="sur-prise"> <template>...</template> <script> var t = document.currentScript.parentElement.querySelectorAll('template'); var defensiveCopy = t.content.cloneNode(); ({ readyCallback: function () { var root = this.createShadowRoot(); root.appendChild(defensiveCopy.cloneNode()); } }); </script> </element> Will create a Custom Element with a prototype with 'message' and 'stack' because those are the own properties of the exception generated at t.content.cloneNode (because I "accidentally" did querySelectorAll instead of querySelector, so t is a NodeList and t.content is undefined; undefined.cloneNode() throws; etc.) Maybe custom element processing should not set up this funkified prototype if the script exits with an error exit? 88403 1 dglazkov 2013-05-29 21:06:06 +0000 Good point! https://dvcs.w3.org/hg/webcomponents/rev/29a89e926f94