如何检查字符是否是Javascript中的字母？
我通过以下方式提取Javascript字符串中的字符：
I am extracting a character in a Javascript string with:
var first = str.charAt(0);
，我想检查它是否是一封信。奇怪的是，它似乎并不像这样的功能存在于Javascript。至少我找不到。
and I would like to check whether it is a letter. Strangely, it does not seem like such functionality exists in Javascript. At least I cannot find it.
如何测试这个？
我相信此插件具有您所寻求的功能： http://xregexp.com/plugins/ （ github链接： https://github.com/slevithan/xregexp ）
I believe this plugin has the capabilities you seek: http://xregexp.com/plugins/ (github link: https://github.com/slevithan/xregexp)
有了它，你可以简单地匹配所有unicode字母与 \p {L} 。
With it you can simply match all unicode letters with \p{L}.
阅读此源文件的标题，以查看其支持的类别： http：// xregexp .com / plugins / xregexp-unicode-categories.js
Read the header of this source file to see which categories it supports: http://xregexp.com/plugins/xregexp-unicode-categories.js