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# Stored XSS in onclick with Full Encoding
Stored XSS in onclick with Full Encoding notes for PortSwigger Web Security Academy labs, including exploitation workflow, payload testing, Burp Suite validation, and remediation context.
### Stored XSS Into onclick Event with Angle Brackets and Double Quotes HTML-encoded and Single Quotes and Backslash Escaped
This lab contains an XSS vulnerability stored in the comment feature: the value of a field (name/author/website) is reused in a `onclick` attribute and encoded — `<` and `>` angle brackets and double quotes are HTML-encoded, while single quotes and backslashes are escaped.
Purpose: to submit a comment to execute `alert()` when clicking on the author's name.
In the `website` area the page injects something like:
```javascript
onclick="var tracker={track(){}};tracker.track('http://test.com');"
```
Simple quotes are represented by the `'` entity. Example:
```javascript
'
```
* When `HTTP://hack.com'test` is sent the `'` page as an apostrophe (so the quote is present on the DOM side).
```javascript
It' a wonderfull day
```
* Take advantage of the fact that `'` becomes an apostrophe to break the JavaScript string and inject a calculation/concatenation that calls `alert()`.
HTTP://hack.com'test
* When `HTTP://hack.com'test` is sent the `'` page as an apostrophe (so the quote is present on the DOM side).
* Take advantage of the fact that `'` becomes an apostrophe to break the JavaScript string and inject a calculation/concatenation that calls `alert()`.
```javascript
http://hack.com' + alert(0) + '
```
---
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