From 218934fa2ed1c702a6d3923d2aa2cc6b43c48684 Mon Sep 17 00:00:00 2001 From: Peter Bengtsson Date: Tue, 8 Dec 2020 14:43:23 -0500 Subject: initial commit --- .../reference/statements/break/index.html | 120 +++++++++++++++++++++ 1 file changed, 120 insertions(+) create mode 100644 files/zh-tw/web/javascript/reference/statements/break/index.html (limited to 'files/zh-tw/web/javascript/reference/statements/break/index.html') diff --git a/files/zh-tw/web/javascript/reference/statements/break/index.html b/files/zh-tw/web/javascript/reference/statements/break/index.html new file mode 100644 index 0000000000..ff72f9d25b --- /dev/null +++ b/files/zh-tw/web/javascript/reference/statements/break/index.html @@ -0,0 +1,120 @@ +--- +title: break +slug: Web/JavaScript/Reference/Statements/break +tags: + - JavaScript + - Statement +translation_of: Web/JavaScript/Reference/Statements/break +--- +

{{jsSidebar("Statements")}}

+ +

break 陳述句會中斷目前的迭代、{{jsxref("Statements/switch", "switch")}} 或 {{jsxref("Statements/label", "label")}} 陳述句,並將程式流程轉到被中斷之陳述句後的陳述句。

+ +
{{EmbedInteractiveExample("pages/js/statement-break.html")}}
+ + + +

語法

+ +
break [label];
+ +
+
label
+
可選的。欲中斷陳述句的標籤 (label) 識別。若不是要中斷迭代或 {{jsxref("Statements/switch", "switch")}},則需加此參數。
+
+ +

說明

+ +

中斷陳述 break 可加上標籤 (label) 參數,使其跳出被標籤的陳述語句。此中斷陳述 break 必須被包含在被標籤的陳述語句中。被標籤的陳述語句可被添加於任一個區塊 (block) 前,而非限定在迴圈陳述。

+ +

範例

+ +

下面函式包含一個中斷陳述 break ,當 i 值為 3 時,中斷 while 迴圈,並回傳 3 * x

+ +
function testBreak(x) {
+  var i = 0;
+
+  while (i < 6) {
+    if (i == 3) {
+      break;
+    }
+    i += 1;
+  }
+
+  return i * x;
+}
+ +

The following code uses break statements with labeled blocks. A break statement must be nested within any label it references. Notice that inner_block is nested within outer_block.

+ +
outer_block: {
+  inner_block: {
+    console.log('1');
+    break outer_block; // breaks out of both inner_block and outer_block
+    console.log(':-('); // skipped
+  }
+  console.log('2'); // skipped
+}
+
+ +

The following code also uses break statements with labeled blocks but generates a Syntax Error because its break statement is within block_1 but references block_2. A break statement must always be nested within any label it references.

+ +
block_1: {
+  console.log('1');
+  break block_2; // SyntaxError: label not found
+}
+
+block_2: {
+  console.log('2');
+}
+
+ +

規範

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('ES1')}}{{Spec2('ES1')}}Initial definition. Unlabeled version.
{{SpecName('ES3')}}{{Spec2('ES3')}}Labeled version added.
{{SpecName('ES5.1', '#sec-12.8', 'Break statement')}}{{Spec2('ES5.1')}} 
{{SpecName('ES6', '#sec-break-statement', 'Break statement')}}{{Spec2('ES6')}} 
{{SpecName('ESDraft', '#sec-break-statement', 'Break statement')}}{{Spec2('ESDraft')}} 
+ +

瀏覽器相容性

+ + + +

{{Compat("javascript.statements.break")}}

+ +

參見

+ + -- cgit v1.2.3-54-g00ecf