Characters that change length on .toLowerCase()

Useful for code that expects data of a certain length, but lowercases it in between checking and using.

Created Apr 11, 2024

Updated May 12, 2025

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CategoryJavaScript Syntax

VisibilityPublic

TypeJS

CharsetUTF-8

Template used:

const c = String.fromCodePoint(i)0x0D
const c_lower = c.toLowerCase()0x0D
if (c_lower.length != c.length){0x0D
    log(i)0x0D
}

Sample payloads

const c = String.fromCodePoint(i)0x0D
const c_lower = c.toLowerCase()0x0D
if (c_lower.length != c.length){0x0D
    alert(i)0x0D
}