Complete XSS Testing Methodology: From Reflection to Full Exploitation

Introduction

Cross-Site Scripting (XSS) is still one of the most common and impactful web vulnerabilities.

Most beginners only test:

alert(1)

But real-world XSS requires much more:

context analysis, DOM sinks, framework behavior, filter bypasses, stored execution, and proper impact validation.

In this guide, I’ll show the practical methodology I use.

Phase 1: Reconnaissance

Start with:

Identify all input points

Query parameters

POST requests

Cookies

Headers

File uploads

JSON/XML payloads

Never test blindly.

Mapping entry points is the foundation.

Phase 2: Context Discovery

Find where input reflects:

HTML Body

HTML Attribute

JavaScript String

Event Handler

Framework Templates

URL Reflection

This decides your payload strategy.

Example:

">

works for attribute context.

Phase 3: DOM XSS

Check dangerous sinks:

innerHTML

document.write()

eval()

setTimeout()

jQuery .html()

Trace:

SOURCE →…