Native.js文档中JS调用原生API时为何常出现undefined错误？

pr什么意思

　　An injector is used to add static code snippet to the or/and of generated HTML files. Hexo run injector before filter is executed. 　　hexo.extend.injector.register(entry, value, to); 　　Where the code will be injected inside the HTML. 　　Support those values: 　　: Inject code snippet right after (Default). 　　: Inject code snippet right before . 　　: Inject code snippet right after . 　　: Inject code snippet right before . 　　A function that returns string is supported. 　　The code snippet to be injected. 　　Which page will code snippets being injected. 　　: Inject to every page (Default). 　　: Only inject to home page (which has helper being ) 　　: Only inject to post pages (which has helper being ) 　　: Only inject to pages (which has helper being ) 　　: Only inject to archive pages (which has helper being ) 　　: Only inject to category pages (which has helper being ) 　　: Only inject to tag pages (which has helper being ) 　　Custom layout name could be used as well, see Writing - Layout. 　　There are other internal functions, see hexojs/hexo#4049 for more details. 　　const css = hexo.extend.helper.get("css").bind(hexo); 　　const js = hexo.extend.helper.get("js").bind(hexo); 　　hexo.extend.injector.register( 　　"head_end", 　　() => { 　　return css( 　　"https://cdn.jsdelivr.net/npm/aplayer@1.10.1/dist/APlayer.min.css", 　　); 　　}, 　　"music", 　　); 　　hexo.extend.injector.register( 　　"body_end", 　　' 123456789101111111111111111111111111111 123456789101111111111111111111111111111 123456789101111111111111111111111111111111111111111