return null by running the steps of "get the current value of the event handler"

hi,here is my confusion:
when use a content attr to set the corresponding event handler to an internal raw uncompiled handler,so I get a event listener registered in the event listener list,but the event handler processing algorithm is runned when this listener is called,and because the current value of event handler is internal raw uncompiled handler(and ), variable callback in event handler processing algorithm will be null,and abort next steps. so can't get event handler called.

here is substep 2 of step 1 of "get the current value of the event handler":
    1.If H's value is an internal raw uncompiled handler, run these substeps:
        1,....
        2.If document is not in a browsing context, or if scripting is enabled for document's browsing context, then return null and abort the algorithm for getting the current value of the event handler.

and here is the first two steps of event handler processing algorithm:
    1, Let callback be the result of getting the current value of the event handler H.
    2, If callback is null, then abort these steps.
    3,...

url is:
http://www.w3.org/TR/2014/REC-html5-20141028/webappapis.html#getting-the-current-value-of-the-event-handler
BTW,sorry for my poor English..
from China