Frontend Security Basics Every Developer Ignores Until It Breaks Production
This topic sounds dramatic because it usually is. Frontend security gets ignored because the UI looks harmless. Then production breaks. Data leaks. Users get hacked. You get blamed. This guide explains the real basics in plain language, with examples teachers can confidently recommend. WHAT FRONTEND SECURITY REALLY MEANS Frontend security is about protecting users and data in the browser. You do not control the browser. Users do. Attackers do. Extensions do. Anything running in the browser is exposed. Your job is damage control. If you assume users behave nicely, you already lost. 1. TRUSTING USER INPUT The most common mistake. Every input is dangerous. Text fields, URLs, headers, cookies. What goes wrong Attackers inject scripts. They steal sessions. They modify your UI. They redirect users. Example A comment box accepts HTML. User enters script tag. Script runs for every visitor. Fix Validate input on the frontend for user experience. Validate again on the ba...