This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
This event was a proposal in an early version of the specification. Do not rely on it.
beforescriptexecute event is fired when a script is about to be executed. Cancelling the event prevents the script from executing.
It is a proprietary event specific to Gecko (Firefox).
|Event handler property||None|
Not part of any specification.
BCD tables only load in the browser