---
id: php-ajax-php
title: "PHP AJAX PHP"
category: "Programming_Language"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["XMLHttpRequest", "PHP AJAX 자동완성"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.88
created_at: 2026-07-04
updated_at: 2026-07-04
review_reason: ""
merge_history: []
tags: ["php", "programming", "w3schools", "ajax", "javascript"]
raw_sources: ["https://www.w3schools.com/php/php_ajax_php.asp"]
applied_in: []
github_commit: ""
---

# [[PHP AJAX PHP]]

## 🎯 한 줄 통찰 (One-line insight)
The classic autocomplete pattern splits work cleanly across the stack — JavaScript's `onkeyup` fires on every keystroke and sends the partial text via `XMLHttpRequest` to a PHP endpoint, while PHP does the actual matching against its name array and returns plain text that JavaScript drops straight into the DOM — meaning the PHP side never touches the DOM and the JS side never touches the data logic. [S1]

## 🧠 핵심 개념 (Core concepts)
- **`onkeyup` event** — triggers the JavaScript function on every keystroke, enabling real-time feedback. [S1]
- **`XMLHttpRequest`** — the JS object used to send the async GET request. [S1]
- **`onreadystatechange`** — a callback fired when the request's state changes; checks `readyState == 4` (done) and `status == 200` (success) before using the response. [S1]
- **Query string parameter passing** — the input's current value is appended to the request URL (`gethint.php?q=" + str`). [S1]
- **PHP-side matching** — `$_REQUEST["q"]` retrieves the query string; `stristr()` performs a case-insensitive substring search against a hardcoded name array. [S1]
- **Plain-text response** — the PHP script just `echo`s the matched name(s); no JSON/XML wrapping needed for this simple case. [S1]

## 📖 세부 내용 (Details)
- JS trigger: `<input type="text" id="fname" name="fname" onkeyup="showHint(this.value)">`. [S1]
- Async request: `var xmlhttp = new XMLHttpRequest(); xmlhttp.onreadystatechange = function() { if (this.readyState == 4 && this.status == 200) { document.getElementById("txtHint").innerHTML = this.responseText; } }; xmlhttp.open("GET", "gethint.php?q=" + str, true); xmlhttp.send();`. [S1]
- PHP matching: `$q = $_REQUEST["q"]; if ($q !== "") { $q = strtolower($q); $len=strlen($q); foreach($a as $name) { if (stristr($q, substr($name, 0, $len))) { ... } } } echo $hint === "" ? "no suggestion" : $hint;`. [S1]

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
소스에서 모순되는 정보는 발견되지 않음.

## 🛠️ 적용 사례 (Applied in summary)
현재 발견된 실제 적용 사례가 없습니다 — 이름 자동완성(입력 시 실시간 제안 표시)이 AJAX+PHP 연동의 대표 실전 사례다. [S1]

## 💻 코드 패턴 (Code patterns)
PHP-side substring matching against user input (PHP):
```php
$q = $_REQUEST["q"];
$hint = "";
if ($q !== "") {
    $q = strtolower($q);
    $len = strlen($q);
    foreach ($a as $name) {
        if (stristr($q, substr($name, 0, $len))) {
            $hint = ($hint === "") ? $name : $hint . ", $name";
        }
    }
}
echo $hint === "" ? "no suggestion" : $hint;
```

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.88
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[PHP Tutorial]]
- **관련 개념:** [[PHP AJAX Intro]], [[PHP AJAX Database]], [[PHP Superglobals Request]]
- **참조 맥락:** JS-PHP 데이터 교환 기초 — 데이터베이스 연동(AJAX Database) 챕터로 이어짐.

## 📚 출처 (Sources)
- [S1] W3Schools — PHP - AJAX and PHP — https://www.w3schools.com/php/php_ajax_php.asp

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