docs(10_Wiki): W3Schools 위키화 — HTML/CSS/JavaScript(core)

W3Schools 튜토리얼을 P-Reinforce v3.1 포맷으로 위키화(영어 본문, 한/영 섹션 헤더).
- Topic_HTML: 59문서 (튜토리얼+예제, 레퍼런스/메타 제외)
- Topic_CSS: 190문서 (메인 + Advanced/Flexbox/Grid/RWD 전체)
- Topic_JavaScript: 120문서 (코어 언어; Temporal/DOM상세/BOM/WebAPI/AJAX/jQuery/Graphics 등은 후속)
각 폴더 00_INDEX.md(MOC) 포함. 코드 verbatim, 미확인분은 "Not found in source" 표기.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

10_Wiki/Topic_JavaScript/JavaScript_Random.md

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+---
+id: javascript-random
+title: "JavaScript Random"
+category: "Frontend"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["Math.random", "random number", "random integer", "getRndInteger", "JS random"]
+duplicate_of: ""
+source_trust_level: "B"
+confidence_score: 0.9
+created_at: 2026-06-23
+updated_at: 2026-06-23
+review_reason: ""
+merge_history: []
+tags: ["javascript", "js", "web", "frontend", "w3schools", "math", "random"]
+raw_sources: ["https://www.w3schools.com/js/js_random.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[JavaScript Random]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+`Math.random()` returns a float in [0, 1); wrapping it in `Math.floor(Math.random() * n)` yields a random integer, and the inclusive-range formula `Math.floor(Math.random() * (max - min + 1)) + min` covers both endpoints. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **`Math.random()`** always returns a number lower than 1 (and ≥ 0). [S1]
+- **Random integers** are produced by combining `Math.random()` with `Math.floor()`. [S1]
+- **Multiplying by `n`** then flooring gives an integer from 0 to n−1; using `n+1` makes the top bound inclusive. [S1]
+- **Adding an offset** (`+ 1`, `+ min`) shifts the range away from 0. [S1]
+- **The inclusive-range function** uses `(max - min + 1)` so that both `min` and `max` are possible results. [S1]
+
+## 🧩 추출된 패턴 (Extracted patterns)
+- **0 to n−1** — `Math.floor(Math.random() * n)`. [S1]
+- **0 to n (inclusive)** — `Math.floor(Math.random() * (n + 1))`. [S1]
+- **1 to n (inclusive)** — `Math.floor(Math.random() * n) + 1`. [S1]
+- **min to max, max excluded** — `Math.floor(Math.random() * (max - min)) + min`. [S1]
+- **min to max, max included** — `Math.floor(Math.random() * (max - min + 1)) + min`. [S1]
+
+## 📖 세부 내용 (Details)
+**Math.random()** — `Math.random()` returns a random number between 0 (inclusive), and 1 (exclusive). `Math.random()` always returns a number lower than 1: [S1]
+```javascript
+// Returns a random number:
+Math.random();
+```
+
+**JavaScript Random Integers** — `Math.random()` used with `Math.floor()` can be used to return random integers. [S1]
+
+Return a random integer from 0 to 9 (both included): [S1]
+```javascript
+// Return a random integer from 0 to 9 (both included):
+Math.floor(Math.random() * 10);
+```
+
+Return a random integer from 0 to 10 (both included): [S1]
+```javascript
+// Return a random integer from 0 to 10 (both included):
+Math.floor(Math.random() * 11);
+```
+
+Return a random integer from 0 to 99 (both included): [S1]
+```javascript
+// Return a random integer from 0 to 99 (both included):
+Math.floor(Math.random() * 100);
+```
+
+Return a random integer from 0 to 100 (both included): [S1]
+```javascript
+// Return a random integer from 0 to 100 (both included):
+Math.floor(Math.random() * 101);
+```
+
+Return a random integer from 1 to 10 (both included): [S1]
+```javascript
+// Return a random integer between 1 and 10 (both included):
+Math.floor(Math.random() * 10) + 1;
+```
+
+Return a random integer from 1 to 100 (both included): [S1]
+```javascript
+// Returns a random integer from 1 to 100 (both included):
+Math.floor(Math.random() * 100) + 1;
+```
+
+**A Proper Random Function** — As you can see from the examples above, it might be a good idea to create a proper random function to use for all random integer purposes. This function returns a random number between `min` (included) and `max` (excluded): [S1]
+```javascript
+function getRndInteger(min, max) {
+  return Math.floor(Math.random() * (max - min) ) + min;
+}
+```
+
+This function returns a random number between `min` and `max` (both included): [S1]
+```javascript
+function getRndInteger(min, max) {
+  return Math.floor(Math.random() * (max - min + 1) ) + min;
+}
+```
+
+## 🛠️ 적용 사례 (Applied in summary)
+The page's own snippets are the canonical applied examples — generating random integers in fixed ranges (0–9, 0–100, 1–100) and the reusable `getRndInteger(min, max)` helpers in both exclusive-max and inclusive-max forms. No external project/commit applications found in the source.
+
+## 💻 코드 패턴 (Code patterns)
+Random integer 0 to n−1:
+```javascript
+Math.floor(Math.random() * 10);   // 0..9
+```
+Random integer 1 to n (inclusive):
+```javascript
+Math.floor(Math.random() * 100) + 1;  // 1..100
+```
+Reusable inclusive-range function:
+```javascript
+function getRndInteger(min, max) {
+  return Math.floor(Math.random() * (max - min + 1) ) + min;
+}
+```
+
+## ⚖️ 비교 및 선택 기준 (Comparison & decision criteria)
+- **Exclusive-max vs inclusive-max** — `getRndInteger` with `(max - min)` excludes `max`; the variant with `(max - min + 1)` includes `max`. Choose based on whether the upper bound should be a possible result. [S1]
+
+## ⚖️ 모순 및 업데이트 (Contradictions & updates)
+No contradictions found in the source.
+
+## ✅ 검증 상태 및 신뢰도
+- **상태:** draft
+- **검증 단계:** conceptual (실제 적용 사례 발견 시 applied/validated로 승격 가능)
+- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
+- **신뢰 점수:** 0.90
+- **중복 검사 결과:** 신규 생성 (New discovery)
+
+## 🔗 지식 그래프 (Knowledge Graph)
+- **상위/루트:** [[JavaScript Tutorial]]
+- **관련 개념:** [[JavaScript Math]], [[JavaScript Numbers]], [[JavaScript Array Sort]]
+- **참조 맥락:** Referenced whenever randomized values or random integer ranges are needed.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — JavaScript Random — https://www.w3schools.com/js/js_random.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-06-23: Initial draft synthesized from the W3Schools "JavaScript Random" page (Astra wiki-curation, P-Reinforce v3.1 format).