Closing whatever tag, attribute or script block you landed in so the browser parses your input as code. Most of XSS is this.
An XSS payload stored as a Google Cloud project name executed months later in the unfiltered project-deletion error message, earning a $5,000 VRP reward, plus the impact argument that got it past a self-XSS classification.
A duplicated q parameter in PayPal's merchant directory let an injected payload break out of script context, producing a reflected XSS that PayPal patched within days.
A Firefox-only reflected XSS on wwwb.search.billmelater.com, achieved by closing out of a style attribute and injecting a fresh script element, which the vendor classified as out of scope.
A payload placed in the URL fragment reached a DOM sink on PayPal's main domain and executed; PayPal closed the report as a duplicate.
