#JavaScript
Cross-Model Audits of AI-Written Code — Process, Not Faith
After using AI to port a calculator from a 35-sheet engineering spreadsheet, how do I know it is correct? This article covers three independent audit rounds by an agent from another provider, the rules to set before starting, confidence levels that keep claims within the evidence, and the classes of errors AI kept making in every round.
Let Clients Pick Photos on a Web Page Without a Login
When the person choosing photos for a website is not comfortable with computers, adding registration and login means the work stops at the login screen. This article covers a photo picker with no authentication at all, but with a server endpoint that checks every value against an allowlist strict enough to leave nothing from arbitrary input, plus limits at every layer and a backup before every write.
A Report Form for a Static Site with No Backend
A calculator site made entirely of static files has no server to handle forms, but users still need a way to report mistakes in the formulas. This article covers the one approach I chose—a single worker file that accepts POST requests on one route, verifies Turnstile on the server using the real client IP, accepts images pasted from the clipboard, and sends email from the network edge—along with three traps that cost me an entire night.
A Cookie Banner That Loads GTM and GA4 Only After Consent
Most cookie banners look good but block nothing, because GTM and GA4 have already loaded from the first line of the page. This article covers a setup that loads the container only after acceptance, puts GA4 inside GTM to prevent double counting, hides AdSense slots initially, and checks that outgoing requests to those services stay at zero.
A Blank Page with No Errors, All Because I Named a Function top
After deployment, the page was blank, the logs had no errors, and node --check found nothing wrong. But the browser stopped the entire script before the first line ran because a function named top collided with window.top. Here are the names to avoid, the script loading order trap, and the Playwright check every project should have.
Images Fail on Mobile in Pages Hidden with display:none
A site switches pages using display:none, but opening another page on mobile leaves blank black images, even though the files return 200 and both fetch and new Image succeed. The culprit is the IntersectionObserver behind loading=lazy not firing when the page changes from none to block, and simply setting loading=eager is still not enough.
A Single-Page PHP and SQLite Document Vault That Keeps Originals
A document photo storage app for government submissions, using photos taken on site with a phone. Each upload produces three files—the display image, the original, and saved crop settings—so adjustments can be made later without losing quality, with automatic migration from JSON to SQLite and web server restrictions on folders containing personal data.
Printing Dozens of Government Forms from HTML with Correct Margins
A government submission document system where users click Print in their browsers and every sheet must fit within its margins, from measuring the actual printable area in millimeters and repeating headers and footers without position fixed, to four image frame types for different documents and automated overflow checks with Playwright instead of inspecting every sheet.
News Stuck for Three Days Because the Feed Wasn't Sorted by Date
The news site's homepage showed the same day's stories for three days straight, even though scheduled jobs ran, translations finished, and every step reported success. The causes were an RSS feed sorted by relevance rather than date, string sorting of pubDate that actually sorted by weekday name, and requesting too few stories, leaving nothing after filtering before the rest even got a look.
Moving Computation from PHP to the Browser: 12 Seconds to 12 ms
A single page ran tens of thousands of subqueries and took 12 seconds to load. I fixed it by precomputing a summary table, sending a single 107 KB dataset, and moving the formulas to the browser, bringing computation down to 12 milliseconds, with a parity test that requires JS results to match PHP on every row.
WAF Returns 406 for Thai Text in POST: Fixing It Without Root
ModSecurity on the host returns 406 for certain Thai sentences in the POST body, preventing forms from saving — but as a hosting tenant, I cannot change the rules myself. This article shows how to isolate the offending text through black-box testing, then work around it with JS encoding on submit + middleware decoding in Laravel.
Porting Excel Formulas to the Web: Floating-Point Traps
Porting engineering formulas from an Excel file to a web calculator produced differences around 1e-13 — not a math bug, but differences in how JS and Excel evaluate floating-point powers and multiplication order, with a method for reading formulas and values separately using openpyxl and building fixtures that actually catch regressions.