Debugger: Difference between revisions

<dd>Either <code>null</code> or a function that SpiderMonkey calls when a call to a debug event handler, breakpoint handler, watchpoint handler, or similar function throws some exception, <i>debugger-exception</i>. Exceptions thrown in the debugger are not propagated to debuggee code; instead, SpiderMonkey calls this function, passing <i>debugger-exception</i> as its sole argument and the <code>Debugger</code> instance as the <code>this</code> value. This function should return a [[#Resumption_Values|resumption value]], which determines how the debuggee should continue. If the uncaught exception hook itself throws an exception, <i>uncaught-hook-exception</i>, SpiderMonkey throws an exception <i>confess-to-debuggee-exception</i> to the debuggee whose message blames the debugger, and includes textual descriptions of <i>uncaught-hook-exception</i> and <i>debugger-exception</i>. If this property's value is <code>null</code>, SpiderMonkey throws an exception to the debuggee whose message blames the debugger, and includes a textual description of <i>debugger-exception</i>.

(The hope here is that some sort of backstop, even if imperfect, will make life easier for debugger developers, especially since an uncaughtExceptionHook has access to browser-level features like <code>alert</code>, which this API's implementation does not.)