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_Operators.md

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+---
+id: javascript-operators
+title: "JavaScript Operators"
+category: "Frontend"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["JS operators", "JavaScript operator types", "arithmetic operators", "assignment operators", "comparison operators", "logical operators", "concatenation operator"]
+duplicate_of: ""
+source_trust_level: "B"
+confidence_score: 0.88
+created_at: 2026-06-23
+updated_at: 2026-06-23
+review_reason: ""
+merge_history: []
+tags: ["javascript", "js", "web", "frontend", "w3schools", "operators"]
+raw_sources: ["https://www.w3schools.com/js/js_operators.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[JavaScript Operators]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+JavaScript operators are used for mathematical and logical computations — the `=` assigns, `+` adds (and concatenates strings), `*` multiplies, and comparison/logical operators evaluate conditions. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **Operators are for mathematical and logical computations** — they perform operations on values and variables. [S1]
+- **Four core single examples** — the assignment operator `=` assigns values, the addition operator `+` adds, the multiplication operator `*` multiplies, and the comparison operator `>` compares. [S1]
+- **Operator categories** — JavaScript operators include Arithmetic, Assignment, Comparison, Logical, and String operators. [S1]
+- **`+` is overloaded** — when used on strings, the `+` operator is called the concatenation operator; if you add a number and a string, the result is a string. [S1]
+- **Comparisons return booleans** — comparison operators always return `true` or `false`, and strings are compared alphabetically. [S1]
+
+## 🧩 추출된 패턴 (Extracted patterns)
+- **Compute into a new variable** — combine two operands with an arithmetic operator and store the result: `let z = x + y;`. [S1]
+- **Compound assignment** — `x += 5` is shorthand for `x = x + 5`. [S1]
+- **Concatenate then assign** — build a string with `+` and a separator: `text1 + " " + text2`. [S1]
+
+## 📖 세부 내용 (Details)
+**Operators are for Mathematical and Logical Computations** [S1]
+The assignment operator (`=`) assigns a value to a variable:
+```javascript
+let x = 10;
+```
+The addition operator (`+`) adds values:
+```javascript
+let x = 5;
+let y = 2;
+let z = x + y;
+```
+The multiplication operator (`*`) multiplies values:
+```javascript
+let x = 5;
+let y = 2;
+let z = x * y;
+```
+A more complex expression mixing addition and multiplication: [S1]
+```javascript
+let a = 3;
+let x = (100 + 50) * a;
+```
+
+**Types of JavaScript Operators** [S1]
+There are different types of JavaScript operators: Arithmetic, Assignment, Comparison, String, Logical, and others.
+
+**JavaScript Arithmetic Operators** [S1]
+Arithmetic operators are used to perform arithmetic on numbers:
+
+| Operator | Description |
+|----------|-------------|
+| + | Addition |
+| - | Subtraction |
+| * | Multiplication |
+| ** | Exponentiation |
+| / | Division |
+| % | Modulus (Division Remainder) |
+| ++ | Increment |
+| -- | Decrement |
+
+**JavaScript String Addition** [S1]
+When used on strings, the `+` operator is called the concatenation operator:
+```javascript
+let text1 = "John";
+let text2 = "Doe";
+let text3 = text1 + " " + text2;
+```
+The `+=` assignment operator can also concatenate:
+```javascript
+let text1 = "What a very ";
+text1 += "nice day";
+```
+
+**Adding Strings and Numbers** [S1]
+If you add a number and a string, the result will be a string:
+```javascript
+let x = 5 + 5;
+let y = "5" + 5;
+let z = "Hello" + 5;
+```
+
+**JavaScript Assignment Operators** [S1]
+Assignment operators assign values to JavaScript variables. For example, `x += 5` is the same as `x = x + 5`:
+```javascript
+let x = 10;
+x += 5;
+```
+
+| Operator | Example | Same As |
+|----------|---------|---------|
+| = | x = y | x = y |
+| += | x += y | x = x + y |
+| -= | x -= y | x = x - y |
+| *= | x *= y | x = x * y |
+| /= | x /= y | x = x / y |
+| %= | x %= y | x = x % y |
+| **= | x **= y | x = x ** y |
+
+**JavaScript Comparison Operators** [S1]
+Comparison operators always return `true` or `false`:
+```javascript
+let x = 5;
+let result = x > 8;
+```
+
+| Operator | Description | Example |
+|----------|-------------|---------|
+| == | equal to | x == 5 |
+| === | equal value and equal type | x === 5 |
+| != | not equal | x != 5 |
+| !== | not equal value or not equal type | x !== 5 |
+| > | greater than | x > 5 |
+| < | less than | x < 5 |
+| >= | greater than or equal to | x >= 5 |
+| <= | less than or equal to | x <= 5 |
+
+Strings are compared alphabetically: [S1]
+```javascript
+let text1 = "A";
+let text2 = "B";
+let result = text1 < text2;
+```
+
+**JavaScript Logical Operators** [S1]
+
+| Operator | Description |
+|----------|-------------|
+| && | logical and |
+| \|\| | logical or |
+| ! | logical not |
+
+## 🛠️ 적용 사례 (Applied in summary)
+The page's own snippets are the canonical applied examples — assigning with `=`, computing with `+`/`*`, concatenating strings, compound-assigning with `+=`, and comparing values/strings. No external project/commit applications found in the source.
+
+## 💻 코드 패턴 (Code patterns)
+Compute and store a result:
+```javascript
+let x = 5;
+let y = 2;
+let z = x + y;
+```
+Concatenate strings with a separator:
+```javascript
+let text3 = text1 + " " + text2;
+```
+Compound assignment:
+```javascript
+let x = 10;
+x += 5;
+```
+
+## ⚖️ 모순 및 업데이트 (Contradictions & updates)
+No contradictions found in the source. The behavior that `"5" + 5` yields a string (`"55"`) rather than `10` is intentional, not a contradiction — `+` concatenates when a string operand is present.
+
+## ✅ 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:** 0.88
+- **중복 검사 결과:** 신규 생성 (New discovery)
+
+## 🔗 지식 그래프 (Knowledge Graph)
+- **상위/루트:** [[JavaScript Tutorial]]
+- **관련 개념:** [[JavaScript Arithmetic]], [[JavaScript Assignment]], [[JavaScript Comparisons]], [[JavaScript Types]]
+- **참조 맥락:** The umbrella reference for the operator-family pages (arithmetic, assignment, comparison, logical) that follow it.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — JavaScript Operators — https://www.w3schools.com/js/js_operators.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-06-23: Initial draft synthesized from the W3Schools "JavaScript Operators" page (Astra wiki-curation, P-Reinforce v3.1 format).