September 2022
Intermediate to advanced
585 pages
8h 17m
Chinese
Content preview from JavaScript 经典实例：第三版
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296
｜
第
11
章
审阅性能数据是确保良好用户体验的重要一步。研究证明，优秀的网站性能可以提
高用户留存率和销售转化率。
11.4
节将进一步探讨潜在的性能问题。
11.3
找出未使用的
JavaScript
代码
11.3.1
问题
应用的性能受到大型
JavaScript
文件的影响。
11.3.2
方案
使用
Chrome
开发者工具中的覆盖率（
Coverage
）功能找出未使用的
JavaScript
代码
（见图
11-4
）。
图
11
-
4
：Chrome 中的覆盖率工具
若想查看有哪些用不到的
JavaScript
代码，需要打开“覆盖率”标签页，步骤如下所示。
1.
按
Command-Option-C
（
Macintosh
）或
Control+Shift+C
（
Windows
或
Linux
）
组合键，打开
Chrome
的开发者工具。
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