Blog
Mert Özen's blog posts on software development, backend, frontend, and DevOps.
Advanced JavaScript Events: Bubbling, Capturing, Event Delegation and CustomEvent
We walk through the capturing, target and bubbling phases, stopPropagation, event delegation with a single listener, the once/passive/signal options, CustomEvent and pointer events, with runnable examples.
Advanced JavaScript Forms: FormData, the Constraint Validation API and Fetch
We collect values with form.elements and FormData, write our own rules with validity and setCustomValidity, catch the invalid event, and send the form with fetch without reloading the page.
JavaScript Web Storage and Cookies: localStorage, sessionStorage and document.cookie
We cover localStorage vs sessionStorage, storing objects with JSON, the cross-tab storage event, quota and security limits, cookie attributes through document.cookie, and why HttpOnly cookies stay invisible.
JavaScript URL, URLSearchParams and the History API: Managing the Address Without a Reload
We take addresses apart with URL and URLSearchParams, look at the hash, compare pushState and replaceState, learn when popstate fires, and write a small framework-free SPA router.
JavaScript Modules in the Browser: import, export, Dynamic import() and Import Maps
We write a first module with type="module", see why file:// fails, and learn named and default exports, live bindings, dynamic import(), import maps and ES2025's JSON modules with import attributes.
Advanced Date Handling in JavaScript: Time Zones, UTC and Formatting with Intl
We see that Date holds a single moment, then cover UTC and ISO 8601 rules, Intl.DateTimeFormat options, "3 days ago" with Intl.RelativeTimeFormat, the daylight saving trap and a first look at Temporal.