2nd/10_Wiki/Topics/Topic_Programming/Topic_JavaScript/JavaScript_Introduction.md

id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit

id	title	category	status	verification_status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	created_at	updated_at	review_reason	merge_history	tags	raw_sources	applied_in	github_commit
javascript-introduction	JavaScript Introduction	Frontend	draft	conceptual		JavaScript JS JS intro ECMAScript client-side scripting		B	0.89	2026-06-23	2026-06-23			javascript js web frontend w3schools	https://www.w3schools.com/js/js_intro.asp

JavaScript Introduction

🎯 한 줄 통찰 (One-line insight)

JavaScript is the programming language of the web — it programs the behavior of web pages, able to read and dynamically change both HTML content and CSS styles. [S1]

🧠 핵심 개념 (Core concepts)

• JavaScript is the programming language of the web — it lets you calculate, manipulate, and validate data, and update/change both HTML and CSS. [S1]
• The three web layers — HTML defines the content, CSS specifies the layout, and JavaScript programs the behavior. [S1]
• The DOM entry point — JavaScript reaches HTML elements through the document, most commonly with document.getElementById(), then reads/writes their content, attributes, and style. [S1]
• Quotes are interchangeable — JavaScript accepts both single ' and double " quotes for strings. [S1]
• Standardized — JavaScript became an ECMA standard in 1997; the official standard is ECMA-262 and the official language name is ECMAScript. [S1]

🧩 추출된 패턴 (Extracted patterns)

• Select → mutate pattern — get a reference to an element (document.getElementById("id")), then assign to a property (.innerHTML, .style.*, an attribute) to change the page. [S1]
• Style via .style object — CSS properties are set in JS using camelCase property names on element.style (e.g. fontSize, not font-size). [S1]
• Show/hide via display — toggling style.display between "none" and "block" hides or reveals an element. [S1]

📖 세부 내용 (Details)

What is JavaScript? JavaScript is the programming language of the web. It can calculate, manipulate, and validate data, and it can update and change both HTML and CSS. [S1]

JavaScript, HTML and CSS The three layers of standard web technology: HTML to define the content of web pages, CSS to specify the layout of web pages, and JavaScript to program the behavior of web pages. [S1]

JavaScript Can Change HTML Content One of many JavaScript HTML methods is getElementById(). It finds an HTML element (by id) and changes the element content (innerHTML): [S1]

document.getElementById("demo").innerHTML = "Hello JavaScript";

JavaScript accepts both double and single quotes:

document.getElementById('demo').innerHTML = 'Hello JavaScript';

JavaScript Can Change HTML Attribute Values JavaScript can change attribute values dynamically — for example, changing the src (source) attribute of an <img> tag in response to user interaction (e.g. a light bulb turning on/off). [S1]

JavaScript Can Change HTML Styles (CSS) Changing the style of an HTML element is a variant of changing an HTML attribute: [S1]

document.getElementById("demo").style.fontSize = "35px";

JavaScript Can Hide HTML Elements Hiding HTML elements can be done by changing the display style: [S1]

document.getElementById("demo").style.display = "none";

JavaScript Can Show HTML Elements Showing hidden HTML elements can also be done by changing the display style: [S1]

document.getElementById("demo").style.display = "block";

Why study JavaScript? JavaScript is one of the three languages all web developers must learn, alongside HTML and CSS. [S1]

History JavaScript was invented by Brendan Eich in 1995 and became an ECMA standard in 1997. [S1]

🛠️ 적용 사례 (Applied in summary)

The page's own snippets are the canonical applied examples — selecting #demo and mutating its innerHTML, style.fontSize, and style.display. No external project/commit applications found in the source.

💻 코드 패턴 (Code patterns)

Select an element and change its content (language: JavaScript):

document.getElementById("demo").innerHTML = "Hello JavaScript";

Change a style:

document.getElementById("demo").style.fontSize = "35px";

Hide / show:

document.getElementById("demo").style.display = "none";
document.getElementById("demo").style.display = "block";

⚖️ 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 Where To, JavaScript Output, JavaScript HTML DOM, HTML JavaScript
• 참조 맥락: The entry point referenced whenever adding interactive behavior to an HTML/CSS page.

📚 출처 (Sources)

• [S1] W3Schools — JavaScript Introduction — https://www.w3schools.com/js/js_intro.asp

📝 변경 이력 (Change history)

• 2026-06-23: Initial draft synthesized from the W3Schools "JavaScript Introduction" page (Astra wiki-curation, P-Reinforce v3.1 format).