Technical fix guide
Deprecated API Usage Heuristic
Page may use deprecated browser APIs (e.g., document.write, synchronous XMLHttpRequest) that can degrade performance or break in future browsers.
Issue ID: TECH-DEPRECATED-API-001
Severity: advisory
Impact: Low
Effort: M
Use this article when
- You need deeper remediation guidance than the issue card can show.
- You want CMS-specific steps before handing the fix to a developer.
- You want a repeatable re-check path after shipping the change.
What this issue is
Page may use deprecated browser APIs (e.g., document.write, synchronous XMLHttpRequest) that can degrade performance or break in future browsers.
Why it matters
Page may use deprecated browser APIs (e.g., document.write, synchronous XMLHttpRequest) that can degrade performance or break in future browsers. This affects crawlability, rendering, and whether the site can be interpreted correctly by search engines.
How we detect it
- FreeSiteAudit flags this issue when the rule for TECH-DEPRECATED-API-001 fails and the page evidence points to Dom body.
- You can usually confirm this by checking the page source or the relevant page settings inside your CMS.
Evidence examples
Check the affected page source, rendered output, or relevant CMS setting to confirm the missing or incorrect element.
How to fix it
- 1Replace document.write() with DOM manipulation methods
- 2Use async/await or fetch() instead of synchronous XMLHttpRequest
- 3Check Chrome DevTools Issues tab for deprecation warnings
How to re-check it
- No deprecation warnings in Chrome DevTools Issues tab
Related tools
This issue is best verified with the full FreeSiteAudit crawl rather than a single-point mini tool.