---
id: w3css-input
title: "W3CSS Input"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["w3-input", "w3-check", "w3-radio", "W3.CSS 입력 폼"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.89
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["w3css", "css-framework", "w3schools", "forms", "input"]
raw_sources: ["https://www.w3schools.com/w3css/w3css_input.asp"]
applied_in: []
github_commit: ""
---

# [[W3CSS Input]]

## 🎯 한 줄 통찰 (One-line insight)
`w3-input` has a bottom border by DEFAULT — the source frames "borderless" as the exception requiring an explicit `w3-border-0` override, meaning W3.CSS's baked-in visual assumption is that text inputs should look like underlined fields (Material Design style) unless you deliberately opt out. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`w3-input`** — text input styling; has a bottom border BY DEFAULT (add `w3-border-0` to remove it, or `w3-border` for a full border). [S1]
- **`w3-animate-input`** — expands the input to 100% width specifically ON FOCUS (not permanently). [S1]
- **`w3-check`** — checkbox styling. [S1]
- **`w3-radio`** — radio button styling. [S1]
- **`w3-select`** — dropdown/select styling. [S1]
- **Label placement is purely structural** — "Top Labels" vs. "Bottom Labels" is just whether the `<label>` markup comes before or after the `<input>` in HTML order — no different classes involved. [S1]
- **Responsive Grid for form layout** — `w3-row-padding` + `w3-third`/`w3-half` lets multiple inputs sit on one row, stacking on small screens. [S1]

## 📖 세부 내용 (Details)
- Default bottom-border input: `<input class="w3-input" type="text">`. [S1]
- Borderless variant: `<input class="w3-input w3-border-0" type="text">`. [S1]
- Focus-expanding input: `<input class="w3-input w3-animate-input" type="text" style="width:30%">`. [S1]
- Checkbox with disabled state: `<input class="w3-check" type="checkbox" checked="checked"> <label>Milk</label> <input class="w3-check" type="checkbox" disabled> <label>Lemon (Disabled)</label>`. [S1]
- Radio group: `<input class="w3-radio" type="radio" name="gender" value="male" checked> <label>Male</label>`. [S1]
- Grid-based form layout: `<div class="w3-row-padding"><div class="w3-third"><input class="w3-input w3-border" type="text" placeholder="One"></div>...</div>`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
- **입력 필드 기본 테두리**: w3-input이 기본적으로 하단 테두리를 가지며, 테두리 없는 형태는 w3-border-0으로 명시적으로 제거해야 한다는 점이 강조됨. [S1]

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — Responsive Grid로 3개 입력 필드를 한 줄에 배치하는 것이 폼 레이아웃의 대표 실전 사례다. [S1]

## 💻 코드 패턴 (Code patterns)
Input focus animation expanding to full width (HTML):
```html
<input class="w3-input w3-animate-input" type="text" style="width:30%">
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **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:** [[W3.CSS Tutorial]]
- **관련 개념:** [[W3CSS Images]], [[W3CSS Badges]], [[W3CSS Grid]]
- **참조 맥락:** Tables/Lists/Forms 섹션의 마지막 — 배지(Badges) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — W3.CSS Input — https://www.w3schools.com/w3css/w3css_input.asp

## 📝 변경 이력 (Change history)
- 2026-07-04: Initial draft synthesized from the W3Schools "W3.CSS Input" page (Astra wiki-curation, P-Reinforce v3.1 format).
