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_Code_Blocks.md

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+---
+id: javascript-code-blocks
+title: "JavaScript Code Blocks"
+category: "Frontend"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["curly braces", "block statement", "standalone block", "block scope", "statement grouping"]
+duplicate_of: ""
+source_trust_level: "B"
+confidence_score: 0.86
+created_at: 2026-06-23
+updated_at: 2026-06-23
+review_reason: ""
+merge_history: []
+tags: ["javascript", "js", "web", "frontend", "w3schools", "code-blocks", "scope", "syntax"]
+raw_sources: ["https://www.w3schools.com/js/js_codeblocks.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[JavaScript Code Blocks]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+A code block is a group of statements wrapped in curly braces `{ }` that are treated as a single unit — and with `let`/`const` it also creates a private scope. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **Curly braces group statements** — a code block is one or more statements enclosed in `{ }`, executed together as a unit. [S1]
+- **Used by language constructs** — functions, `if/else`, `for`, and `while` all use code blocks to hold their body. [S1]
+- **Blocks define scope** — variables declared with `let` and `const` inside a block are block-scoped and accessible only within that block. [S1]
+- **Standalone blocks exist** — a `{ }` block can stand on its own (not attached to a function or control statement) purely to create a local scope for `let`/`const` variables. [S1]
+- **Benefits of blocks** — encapsulation, use of temporary variables, and organized code that avoids name conflicts while staying readable. [S1]
+
+## 🧩 추출된 패턴 (Extracted patterns)
+- **Wrap a body in `{ }`** — every function/condition/loop body is a code block. [S1]
+- **Use a standalone block for a temporary scope** — `{ let x = ...; }` confines short-lived variables and prevents leaks into the surrounding scope. [S1]
+
+## 📖 세부 내용 (Details)
+**Curly Braces**
+JavaScript code blocks are groups of statements enclosed in curly braces `{ }`. They are essential for controlling the flow of execution and for defining variable scope. [S1]
+
+**Code Blocks and Statements**
+A code block lets multiple statements be treated as a single unit. Code blocks are required by functions, `if` statements, and loops. [S1]
+
+A function uses a code block: [S1]
+```javascript
+function myFunction() {
+  // This is a code block
+}
+```
+
+An `if...else` statement uses code blocks: [S1]
+```javascript
+if (condition) {
+  // This is a code block
+} else {
+  // This is a code block
+}
+```
+
+A `for` loop uses a code block: [S1]
+```javascript
+for (expression 1; expression 2; expression 3) {
+  // This is a code block
+}
+```
+
+A `while` loop uses a code block: [S1]
+```javascript
+while (condition) {
+  // This is a code block
+}
+```
+
+**Defining Scope**
+Variables declared with `let` and `const` inside a code block are block-scoped — they are accessible only within that specific block: [S1]
+```javascript
+{
+  let x = 10;
+  // x is accessible here
+}
+// x is not accessible here
+```
+
+**Standalone Blocks**
+A code block can exist independently, without being attached to a function or control structure, simply to create a scope for `let` and `const` variables: [S1]
+```javascript
+{
+  let x = 10;
+  let y = 100;
+  let areal = x * y;
+}
+```
+Benefits of standalone blocks include encapsulation (variables are confined to the block scope), use of temporary variables, and organized code that prevents name conflicts while maintaining readability. [S1]
+
+## 🛠️ 적용 사례 (Applied in summary)
+The page's snippets are the applied cases: bodies of functions, `if/else`, `for`, and `while`, plus a standalone `{ }` block used to scope temporary variables (`x`, `y`, `areal`). No external project/commit applications found in the source.
+
+## 💻 코드 패턴 (Code patterns)
+Block-scoped variables (language: JavaScript):
+```javascript
+{
+  let x = 10;
+  // x is accessible here
+}
+// x is not accessible here
+```
+Standalone block as a temporary scope:
+```javascript
+{
+  let x = 10;
+  let y = 100;
+  let areal = x * y;
+}
+```
+
+## ⚖️ 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:** 0.86
+- **중복 검사 결과:** 신규 생성 (New discovery)
+
+## 🔗 지식 그래프 (Knowledge Graph)
+- **상위/루트:** [[JavaScript Tutorial]]
+- **관련 개념:** [[JavaScript Scope]], [[JavaScript var let const]], [[JavaScript Functions]], [[JavaScript If Else]]
+- **참조 맥락:** Referenced when explaining how `{ }` both groups statements and confines `let`/`const` variables.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — JavaScript Code Blocks — https://www.w3schools.com/js/js_codeblocks.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-06-23: Initial draft synthesized from the W3Schools "JavaScript Code Blocks" page (Astra wiki-curation, P-Reinforce v3.1 format).