2nd/10_Wiki/Topic_JavaScript/JavaScript_Strings.md

---
id: javascript-strings
title: "JavaScript Strings"
category: "Frontend"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["strings", "JS strings", "string literals", "text values", "string length"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.89
created_at: 2026-06-23
updated_at: 2026-06-23
review_reason: ""
merge_history: []
tags: ["javascript", "js", "web", "frontend", "w3schools", "strings", "quotes", "escape-characters"]
raw_sources: ["https://www.w3schools.com/js/js_strings.asp"]
applied_in: []
github_commit: ""
---

# [[JavaScript Strings]]

## 🎯 한 줄 통찰 (One-line insight)
A JavaScript string is zero or more characters written inside quotes — single, double, or backticks all work — and you measure it with `.length`, escape special characters with `\`, and should avoid wrapping strings in `new String()` objects. [S1]

## 🧠 핵심 개념 (Core concepts)
- **A string is text in quotes** — a JavaScript string is zero or more characters written inside quotes. [S1]
- **Single or double quotes are equivalent** — `"Volvo XC60"` and `'Volvo XC60'` are the same. [S1]
- **Quotes inside quotes** — you can put quotes inside a string as long as the inner quotes differ from the outer ones. [S1]
- **Template strings (ES6)** — backtick-enclosed strings allow flexible use of both quote types and span multiple lines. [S1]
- **`.length`** — the `length` property returns the number of characters in a string. [S1]
- **Escape character `\`** — the backslash escapes special characters so they can appear inside a string. [S1]
- **Strings are primitives, not objects** — `new String()` creates an object; the page warns not to create String objects because they complicate code and slow execution. [S1]

## 🧩 추출된 패턴 (Extracted patterns)
- **Mix quote styles to embed quotes** — choose an outer quote type different from the quote characters you need inside the text. [S1]
- **Escape when you cannot switch quote types** — use `\"`, `\'`, or `\\` to embed the same quote/backslash literally. [S1]
- **Break long lines after an operator** — split a long statement by concatenating string pieces with `+`. [S1]
- **Avoid `new String()`** — keep strings as primitives so `===` comparisons behave intuitively. [S1]

## 📖 세부 내용 (Details)
**Using Quotes**
A JavaScript string is zero or more characters written inside quotes. [S1]
```javascript
let text = "John Doe";
```
You can use single or double quotes: [S1]
```javascript
let carName1 = "Volvo XC60";  // Double quotes
let carName2 = 'Volvo XC60';  // Single quotes
```

**Quotes Inside Quotes**
You can use quotes inside a string, as long as they don't match the quotes surrounding the string: [S1]
```javascript
let answer1 = "It's alright";
let answer2 = "He is called 'Johnny'";
let answer3 = 'He is called "Johnny"';
```

**Template Strings (ES6)**
Backtick-enclosed strings let you use both quote types freely inside the text: [S1]
```javascript
let text = `He's often called "Johnny"`;
```

**String Length**
To find the length of a string, use the built-in `length` property: [S1]
```javascript
let text = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
let length = text.length;
```

**Escape Characters**
Because strings are wrapped in quotes, JavaScript misunderstands a quote inside a string unless it is escaped with the backslash escape character. The escape character `\` turns special characters into string characters. Escape sequences include `\'` (single quote), `\"` (double quote), `\\` (backslash), and the control characters `\b`, `\f`, `\n`, `\r`, `\t`, `\v`. [S1]

Escaping a double quote inside a double-quoted string: [S1]
```javascript
let text = "We are the so-called \"Vikings\" from the north.";
```
Escaping a single quote inside a single-quoted string: [S1]
```javascript
let text = 'It\'s alright.';
```
Escaping a backslash: [S1]
```javascript
let text = "The character \\ is called backslash.";
```

**Breaking Long Code Lines**
The safest way to break a statement is after an operator, or to break a string with string concatenation: [S1]
```javascript
document.getElementById("demo").innerHTML = "Hello " + "Dolly!";
```

**Multiline Template Strings**
Template strings (backticks) allow multiline strings: [S1]
```javascript
let text = `The quick
brown fox
jumps over
the lazy dog`;
```

**JavaScript Strings as Objects**
Normally strings are primitive values created from literals (`let x = "John";`), but they can also be defined as objects with the `new` keyword (`let y = new String("John");`). [S1]

> Warning: Do not create String objects. The `new` keyword complicates the code and slows down execution speed. [S1]

When comparing a primitive string with a String object, `==` (value comparison) returns `true` but `===` (value and type comparison) returns `false`, and comparing two String objects always returns `false`. [S1]

## 🛠️ 적용 사례 (Applied in summary)
The page's own snippets are the canonical applied examples — declaring strings with each quote style, mixing/escaping quotes, reading `.length`, concatenating to break long lines, and contrasting primitive strings with `new String()` objects. No external project/commit applications found in the source.

## 💻 코드 패턴 (Code patterns)
Declare with either quote style:
```javascript
let carName1 = "Volvo XC60";  // Double quotes
let carName2 = 'Volvo XC60';  // Single quotes
```
Escape special characters:
```javascript
let text = "We are the so-called \"Vikings\" from the north.";
```
Measure length:
```javascript
let text = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
let length = text.length;
```

## ⚖️ 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:** 0.89
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[JavaScript Tutorial]]
- **관련 개념:** [[JavaScript String Templates]], [[JavaScript String Methods]], [[JavaScript String Search]], [[JavaScript Data Types]]
- **참조 맥락:** The foundation for all text handling in JavaScript, referenced before string methods, templates, and searching.

## 📚 출처 (Sources)
- [S1] W3Schools — JavaScript Strings — https://www.w3schools.com/js/js_strings.asp

## 📝 변경 이력 (Change history)
- 2026-06-23: Initial draft synthesized from the W3Schools "JavaScript Strings" page (Astra wiki-curation, P-Reinforce v3.1 format).