Userscript Event Monitoring And Error Handling

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

Audit 0.4.1 · source sha 04e912cff54b · 14 Oct 2026Report an issue or request a re-scan

• PublisherECNU-ICALK GitHub organizationOwner of the repository this skill is read from
• Source folderECNU-ICALK/AutoSkill/SkillBank/ConvSkill/english_gpt4_8_GLM4.7/userscript-event-monitoring-and-error-handlingThe exact folder we audited
• LicenceNot declaredAs the repository states it
• Commit pinned for this verdict04e912cff54bA new audit runs when the source changes
• Repository statusNot archivedLast push 157 days ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: A reusable pattern for monitoring page events (AJAX, DOM, visibility) with per-event-type throttling, and safely extracting/parsing error messages using XPath with conditional logic.

---
id: "a38ddcee-2398-4e1b-afe3-050471c54bb4"
name: "Userscript Event Monitoring and Error Handling"
description: "A reusable pattern for monitoring page events (AJAX, DOM, visibility) with per-event-type throttling, and safely extracting/parsing error messages using XPath with conditional logic."
version: "0.1.0"
tags:
  - "userscript"
  - "event-monitoring"
  - "error-handling"
  - "xpath"
  - "throttling"
triggers:
  - "monitor page events userscript"
  - "throttle event logging per type"
  - "extract error message xpath safely"
  - "handle error messages with conditional logic"
  - "userscript event listener"
---

# Userscript Event Monitoring and Error Handling

A reusable pattern for monitoring page events (AJAX, DOM, visibility) with per-event-type throttling, and safely extracting/parsing error messages using XPath with conditional logic.

## Prompt

# Role & Objective
Act as a Userscript Developer. Create a script to monitor page events and handle error messages safely.

# Operational Rules & Constraints
1. **Event Monitoring**: Monitor XMLHttpRequest (loadstart, progress, load, error, abort), DOM mutations (MutationObserver), page visibility (visibilitychange), and page unload (beforeunload).
2. **Throttling**: Implement per-event-type throttling. Use a dictionary/object to track the last log time for each event type separately. Do not use a global timestamp that blocks all events.
3. **Error Extraction**: Create a function to extract text content using XPath. Wrap `document.evaluate` in a try-catch block. Return `null` if the node does not exist or an error occurs.
4. **Error Matching**: Use `String.prototype.includes()` to check if the error message contains specific text fragments. Implement conditional logic (if/else) to perform different actions based on the matched text.
5. **Variable Safety**: When incrementing numeric variables (e.g., counters, retries), explicitly cast them to `Number()` before addition to prevent string concatenation.

# Anti-Patterns
- Do not use a global throttle variable that blocks all event types.
- Do not assume XPath nodes always exist; always handle missing nodes gracefully.
- Do not perform arithmetic on variables without ensuring they are numbers.

## Triggers

- monitor page events userscript
- throttle event logging per type
- extract error message xpath safely
- handle error messages with conditional logic
- userscript event listener

Excerpt, first 2,426 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

git clone https://github.com/ECNU-ICALK/AutoSkill
git -C AutoSkill checkout 04e912cff54b

Works in

1. 2026-10-14
   ✓SAFE B 89 / 100

   first audit · source 04e912cff54b

Questions about Userscript Event Monitoring And Error Handling

• github.com/ECNU-ICALK/AutoSkill/tree/main/SkillBank/ConvSkill/en — the audited source at commit 04e912cff54b and every finding aboveObserved · 14 Oct 2026

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