---
title: JavaScript リファレンス
slug: Web/JavaScript/Reference
tags:
  - Code
  - ECMAScript
  - ECMAScript6
  - ES6
  - JS
  - JavaScript
  - Landing page
  - Reference
  - es
  - 'l10n:priority'
  - programming
translation_of: Web/JavaScript/Reference
---
<div>{{JsSidebar}}</div>

<p>MDN のこの JavaScript セクションは、JavaScript 言語についての情報倉庫となっています。詳しくは<a href="/ja/docs/Web/JavaScript/Reference/About">このリファレンスについて</a>を読んでください。</p>

<h2 id="Built-ins" name="Built-ins">組み込み</h2>

<p><a href="/ja/docs/Web/JavaScript/Reference/Global_Objects">JavaScript の標準組み込みオブジェクト</a>、そのメソッドとプロパティです。。</p>

<ul class="card-grid">
 <li>
  <h4 id="Value_properties" name="Value_properties">値プロパティ</h4>

  <ul>
   <li>{{JSxRef("Infinity")}}</li>
   <li>{{JSxRef("NaN")}}</li>
   <li>{{JSxRef("undefined")}}</li>
   <li>{{JSxRef("globalThis")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Function_properties" name="Function_properties">関数プロパティ</h4>

  <ul>
   <li>{{JSxRef("Global_Objects/eval", "eval()")}}</li>
   <li>{{JSxRef("Global_Objects/isFinite", "isFinite()")}}</li>
   <li>{{JSxRef("Global_Objects/isNaN", "isNaN()")}}</li>
   <li>{{JSxRef("Global_Objects/parseFloat", "parseFloat()")}}</li>
   <li>{{JSxRef("Global_Objects/parseInt", "parseInt()")}}</li>
   <li>{{JSxRef("Global_Objects/decodeURI", "decodeURI()")}}</li>
   <li>{{JSxRef("Global_Objects/decodeURIComponent", "decodeURIComponent()")}}</li>
   <li>{{JSxRef("Global_Objects/encodeURI", "encodeURI()")}}</li>
   <li>{{JSxRef("Global_Objects/encodeURIComponent", "encodeURIComponent()")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Fundamental_objects" name="Fundamental_objects">基本オブジェクト</h4>

  <ul>
   <li>{{JSxRef("Object")}}</li>
   <li>{{JSxRef("Function")}}</li>
   <li>{{JSxRef("Boolean")}}</li>
   <li>{{JSxRef("Symbol")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Error_objects" name="Error_objects">エラーオブジェクト</h4>

  <ul>
   <li>{{JSxRef("Error")}}</li>
   <li>{{JSxRef("AggregateError")}}</li>
   <li>{{JSxRef("EvalError")}}</li>
   <li>{{JSxRef("InternalError")}}</li>
   <li>{{JSxRef("RangeError")}}</li>
   <li>{{JSxRef("ReferenceError")}}</li>
   <li>{{JSxRef("SyntaxError")}}</li>
   <li>{{JSxRef("TypeError")}}</li>
   <li>{{JSxRef("URIError")}}</li>
  </ul>
 </li>
</ul>

<ul class="card-grid">
 <li>
  <h4 id="Numbers_dates" name="Numbers_dates">数値と日付</h4>

  <ul>
   <li>{{JSxRef("Number")}}</li>
   <li>{{JSxRef("BigInt")}}</li>
   <li>{{JSxRef("Math")}}</li>
   <li>{{JSxRef("Date")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Text_processing" name="Text_processing">テキスト処理</h4>

  <ul>
   <li>{{JSxRef("String")}}</li>
   <li>{{JSxRef("RegExp")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Indexed_Collections" name="Indexed_Collections">インデックス付きコレクション</h4>

  <ul>
   <li>{{JSxRef("Array")}}</li>
   <li>{{JSxRef("Int8Array")}}</li>
   <li>{{JSxRef("Uint8Array")}}</li>
   <li>{{JSxRef("Uint8ClampedArray")}}</li>
   <li>{{JSxRef("Int16Array")}}</li>
   <li>{{JSxRef("Uint16Array")}}</li>
   <li>{{JSxRef("Int32Array")}}</li>
   <li>{{JSxRef("Uint32Array")}}</li>
   <li>{{JSxRef("Float32Array")}}</li>
   <li>{{JSxRef("Float64Array")}}</li>
   <li>{{JSxRef("BigInt64Array")}}</li>
   <li>{{JSxRef("BigUint64Array")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Keyed_collections" name="Keyed_collections">キー付きコレクション</h4>

  <ul>
   <li>{{JSxRef("Map")}}</li>
   <li>{{JSxRef("Set")}}</li>
   <li>{{JSxRef("WeakMap")}}</li>
   <li>{{JSxRef("WeakSet")}}</li>
  </ul>
 </li>
</ul>

<ul class="card-grid">
 <li>
  <h4 id="Structured_data" name="Structured_data">構造化データ</h4>

  <ul>
   <li>{{JSxRef("ArrayBuffer")}}</li>
   <li>{{JSxRef("SharedArrayBuffer")}}</li>
   <li>{{JSxRef("Atomics")}}</li>
   <li>{{JSxRef("DataView")}}</li>
   <li>{{JSxRef("JSON")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Control_abstraction" name="Control_abstraction">抽象化の制御</h4>

  <ul>
   <li>{{JSxRef("GeneratorFunction")}}</li>
   <li>{{JSxRef("AsyncGeneratorFunction")}}</li>
   <li>{{JSxRef("Generator")}}</li>
   <li>{{JSxRef("AsyncGenerator")}}</li>
   <li>{{JSxRef("AsyncFunction")}}</li>
   <li>{{JSxRef("Promise")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Reflection" name="Reflection">リフレクション</h4>

  <ul>
   <li>{{JSxRef("Reflect")}}</li>
   <li>{{JSxRef("Proxy")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Internationalization" name="Internationalization">国際化</h4>

  <ul>
   <li>{{JSxRef("Intl")}}</li>
   <li>{{JSxRef("Global_Objects/Intl/Collator", "Intl.Collator")}}</li>
   <li>{{JSxRef("Global_Objects/Intl/DateTimeFormat", "Intl.DateTimeFormat")}}</li>
   <li>{{JSxRef("Global_Objects/Intl/DisplayNames", "Intl.DisplayNames")}}</li>
   <li>{{JSxRef("Global_Objects/Intl/ListFormat", "Intl.ListFormat")}}</li>
   <li>{{JSxRef("Global_Objects/Intl/Locale", "Intl.Locale")}}</li>
   <li>{{JSxRef("Global_Objects/Intl/NumberFormat", "Intl.NumberFormat")}}</li>
   <li>{{JSxRef("Global_Objects/Intl/PluralRules", "Intl.PluralRules")}}</li>
   <li>{{JSxRef("Global_Objects/Intl/RelativeTimeFormat", "Intl.RelativeTimeFormat")}}</li>
  </ul>
 </li>
</ul>

<ul class="card-grid">
 <li>
  <h4 id="WebAssembly">WebAssembly</h4>

  <ul>
   <li>{{JSxRef("WebAssembly")}}</li>
   <li>{{JSxRef("WebAssembly.Module")}}</li>
   <li>{{JSxRef("WebAssembly.Instance")}}</li>
   <li>{{JSxRef("WebAssembly.Memory")}}</li>
   <li>{{JSxRef("WebAssembly.Table")}}</li>
   <li>{{JSxRef("WebAssembly.CompileError")}}</li>
   <li>{{JSxRef("WebAssembly.LinkError")}}</li>
   <li>{{JSxRef("WebAssembly.RuntimeError")}}</li>
  </ul>
 </li>
</ul>

<h2 id="Statements" name="Statements">文</h2>

<p><a href="/ja/docs/Web/JavaScript/Reference/Statements">JavaScript の文と宣言</a></p>

<ul class="card-grid">
 <li>
  <h4 id="Control_flow" name="Control_flow">制御フロー</h4>

  <ul>
   <li>{{jsxref("Statements/block", "ブロック", "", 1)}}</li>
   <li>{{jsxref("Statements/break", "break")}}</li>
   <li>{{jsxref("Statements/continue", "continue")}}</li>
   <li>{{jsxref("Statements/Empty", "空文", "", 1)}}</li>
   <li>{{jsxref("Statements/if...else", "if...else")}}</li>
   <li>{{jsxref("Statements/switch", "switch")}}</li>
   <li>{{jsxref("Statements/throw", "throw")}}</li>
   <li>{{jsxref("Statements/try...catch", "try...catch")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Declarations" name="Declarations">宣言</h4>

  <ul>
   <li>{{jsxref("Statements/var", "var")}}</li>
   <li>{{jsxref("Statements/let", "let")}}</li>
   <li>{{jsxref("Statements/const", "const")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Functions_and_classes" name="Functions_and_classes">関数とクラス</h4>

  <ul>
   <li>{{jsxref("Statements/function", "function")}}</li>
   <li>{{jsxref("Statements/function*", "function*")}}</li>
   <li>{{jsxref("Statements/async_function", "非同期関数", "", 1)}}</li>
   <li>{{jsxref("Statements/return", "return")}}</li>
   <li>{{jsxref("Statements/class", "class")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Iterations" name="Iterations">反復処理</h4>

  <ul>
   <li>{{jsxref("Statements/do...while", "do...while")}}</li>
   <li>{{jsxref("Statements/for", "for")}}</li>
   <li>{{jsxref("Statements/for_each...in", "for each...in")}}</li>
   <li>{{jsxref("Statements/for...in", "for...in")}}</li>
   <li>{{jsxref("Statements/for...of", "for...of")}}</li>
   <li>{{jsxref("Statements/for-await...of", "for await...of")}}</li>
   <li>{{jsxref("Statements/while", "while")}}</li>
  </ul>
 </li>
</ul>

<ul class="card-grid">
 <li>
  <h4 id="Other" name="Other">その他</h4>

  <ul>
   <li>{{jsxref("Statements/debugger", "debugger")}}</li>
   <li>{{jsxref("Statements/export", "export")}}</li>
   <li>{{jsxref("Statements/import", "import")}}</li>
   <li>{{jsxref("Statements/label", "label")}}</li>
   <li>{{jsxref("Statements/with", "with")}}</li>
  </ul>
 </li>
</ul>

<h2 id="Expressions_and_operators" name="Expressions_and_operators">式と演算子</h2>

<p><a href="/ja/docs/Web/JavaScript/Reference/Operators">JavaScript の式と演算子</a></p>

<ul class="card-grid">
 <li>
  <h4 id="Primary_expressions" name="Primary_expressions">主要な式</h4>

  <ul>
   <li>{{JSxRef("Operators/this", "this")}}</li>
   <li>{{JSxRef("Operators/function", "function")}}</li>
   <li>{{JSxRef("Operators/class", "class")}}</li>
   <li>{{JSxRef("Operators/function*", "function*")}}</li>
   <li>{{JSxRef("Operators/yield", "yield")}}</li>
   <li>{{JSxRef("Operators/yield*", "yield*")}}</li>
   <li>{{JSxRef("Operators/async_function", "非同期関数", "", 1)}}</li>
   <li>{{JSxRef("Operators/await", "await")}}</li>
   <li>{{JSxRef("Global_Objects/Array", "[]")}}</li>
   <li>{{JSxRef("Operators/Object_initializer", "{}")}}</li>
   <li>{{JSxRef("Global_Objects/RegExp", "/ab+c/i")}}</li>
   <li>{{JSxRef("Operators/Grouping", "( )")}}</li>
   <li>{{JSxRef("null")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Left-hand-side_expressions" name="Left-hand-side_expressions">左辺式</h4>

  <ul>
   <li>{{JSxRef("Operators/Property_accessors", "プロパティアクセサー", "", 1)}}</li>
   <li>{{JSxRef("Operators/new", "new")}}</li>
   <li>{{JSxRef("Operators/new%2Etarget", "new.target")}}</li>
   <li>{{JSxRef("Operators/super", "super")}}</li>
   <li>{{JSxRef("Operators/Spread_syntax", "...obj")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Increment_decrement" name="Increment_decrement">インクリメント &amp; デクリメント</h4>

  <ul>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "A++", "#Increment")}}</li>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "A--", "#Decrement")}}</li>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "++A", "#Increment")}}</li>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "--A", "#Decrement")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Unary_operators" name="Unary_operators">単項演算子</h4>

  <ul>
   <li>{{JSxRef("Operators/delete", "delete")}}</li>
   <li>{{JSxRef("Operators/void", "void")}}</li>
   <li>{{JSxRef("Operators/typeof", "typeof")}}</li>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "+", "#Unary_plus")}}</li>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "-", "#Unary_negation")}}</li>
   <li>{{JSxRef("Operators/Bitwise_Operators", "~", "#Bitwise_NOT")}}</li>
   <li>{{JSxRef("Operators/Logical_Operators", "!", "#Logical_NOT")}}</li>
  </ul>
 </li>
</ul>

<ul class="card-grid">
 <li>
  <h4 id="Arithmetic_operators" name="Arithmetic_operators">算術演算子</h4>

  <ul>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "+", "#Addition")}}</li>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "-", "#Subtraction")}}</li>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "/", "#Division")}}</li>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "*", "#Multiplication")}}</li>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "%", "#Remainder")}}</li>
   <li>{{JSxRef("Operators/Arithmetic_Operators", "**", "#Exponentiation")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Relational_operators" name="Relational_operators">関係演算子</h4>

  <ul>
   <li>{{JSxRef("Operators/in", "in")}}</li>
   <li>{{JSxRef("Operators/instanceof", "instanceof")}}</li>
   <li>{{JSxRef("Operators/Comparison_Operators", "&lt;", "#Less_than_operator")}}</li>
   <li>{{JSxRef("Operators/Comparison_Operators", "&gt;", "#Greater_than_operator")}}</li>
   <li>{{JSxRef("Operators/Comparison_Operators", "&lt;=", "#Less_than_or_equal_operator")}}</li>
   <li>{{JSxRef("Operators/Comparison_Operators", "&gt;=", "#Greater_than_or_equal_operator")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Equality_operators" name="Equality_operators">等価演算子</h4>

  <ul>
   <li>{{JSxRef("Operators/Comparison_Operators", "==", "#Equality")}}</li>
   <li>{{JSxRef("Operators/Comparison_Operators", "!=", "#Inequality")}}</li>
   <li>{{JSxRef("Operators/Comparison_Operators", "===", "#Identity")}}</li>
   <li>{{JSxRef("Operators/Comparison_Operators", "!==", "#Nonidentity")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Bitwise_shift_operators" name="Bitwise_shift_operators">シフト演算子</h4>

  <ul>
   <li>{{JSxRef("Operators/Bitwise_Operators", "&lt;&lt;", "#Left_shift")}}</li>
   <li>{{JSxRef("Operators/Bitwise_Operators", "&gt;&gt;", "#Right_shift")}}</li>
   <li>{{JSxRef("Operators/Bitwise_Operators", "&gt;&gt;&gt;", "#Unsigned_right_shift")}}</li>
  </ul>
 </li>
</ul>

<ul class="card-grid">
 <li>
  <h4 id="Binary_bitwise_operators" name="Binary_bitwise_operators">ビット演算子</h4>

  <ul>
   <li>{{JSxRef("Operators/Bitwise_Operators", "&amp;", "#Bitwise_AND")}}</li>
   <li>{{JSxRef("Operators/Bitwise_Operators", "|", "#Bitwise_OR")}}</li>
   <li>{{JSxRef("Operators/Bitwise_Operators", "^", "#Bitwise_XOR")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Binary_logical_operators" name="Binary_logical_operators">論理演算子</h4>

  <ul>
   <li>{{JSxRef("Operators/Logical_Operators", "&amp;&amp;", "#Logical_AND")}}</li>
   <li>{{JSxRef("Operators/Logical_Operators", "||", "#Logical_OR")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Conditional_ternary_operator" name="Conditional_ternary_operator">条件（三項）演算子</h4>

  <ul>
   <li>{{JSxRef("Operators/Conditional_Operator", "(condition ? ifTrue : ifFalse)")}}</li>
  </ul>
 </li>
 <li>
  <h4 id="Assignment_operators" name="Assignment_operators">代入演算子</h4>

  <ul>
   <li>{{JSxRef("Operators/Assignment_Operators", "=", "#Assignment")}}</li>
   <li>{{JSxRef("Operators/Assignment_Operators", "*=", "#Multiplication_assignment")}}</li>
   <li>{{JSxRef("Operators/Assignment_Operators", "/=", "#Division_assignment")}}</li>
   <li>{{JSxRef("Operators/Assignment_Operators", "%=", "#Remainder_assignment")}}</li>
   <li>{{JSxRef("Operators/Assignment_Operators", "+=", "#Addition_assignment")}}</li>
   <li>{{JSxRef("Operators/Assignment_Operators", "-=", "#Subtraction_assignment")}}</li>
   <li>{{JSxRef("Operators/Assignment_Operators", "&lt;&lt;=", "#Left_shift_assignment")}}</li>
   <li>{{JSxRef("Operators/Assignment_Operators", "&gt;&gt;=", "#Right_shift_assignment")}}</li>
   <li>{{JSxRef("Operators/Assignment_Operators", "&gt;&gt;&gt;=", "#Unsigned_right_shift_assignment")}}</li>
   <li>{{JSxRef("Operators/Assignment_Operators", "&amp;=", "#Bitwise_AND_assignment")}}</li>
   <li>{{JSxRef("Operators/Assignment_Operators", "^=", "#Bitwise_XOR_assignment")}}</li>
   <li>{{JSxRef("Operators/Assignment_Operators", "|=", "#Bitwise_OR_assignment")}}</li>
   <li>{{JSxRef("Operators/Destructuring_assignment", "[a, b] = [1, 2]")}}</li>
   <li>{{JSxRef("Operators/Destructuring_assignment", "{a, b} = {a:1, b:2}")}}</li>
  </ul>
 </li>
</ul>

<h2 id="Functions" name="Functions">関数</h2>

<p>この章では、アプリケーションの開発で <a href="/ja/docs/Web/JavaScript/Reference/Functions">JavaScript の関数</a> をどう使うかを説明しています。</p>

<ul>
 <li><a href="/ja/docs/Web/JavaScript/Reference/Functions/arguments"><code>arguments</code></a></li>
 <li><a href="/ja/docs/Web/JavaScript/Reference/Functions/Arrow_functions">アロー関数</a></li>
 <li><a href="/ja/docs/Web/JavaScript/Reference/Functions/Default_parameters">デフォルト引数</a> (default parameter)</li>
 <li><a href="/ja/docs/Web/JavaScript/Reference/Functions/rest_parameters">残余引数</a> (rest parameter)</li>
</ul>

<h2 id="Additional_reference_pages" name="Additional_reference_pages">追加のリファレンスページ</h2>

<ul>
 <li><a href="/ja/docs/Web/JavaScript/Reference/Lexical_grammar">字句文法</a></li>
 <li><a href="/ja/docs/Web/JavaScript/Data_structures">データ型とデータ構造</a></li>
 <li><a href="/ja/docs/Web/JavaScript/Reference/Strict_mode">Strict モード</a></li>
 <li><a href="/ja/docs/Web/JavaScript/Reference/Deprecated_and_obsolete_features">非推奨の機能</a></li>
</ul>