在JavaScript中转换HTML为纯文本并保留链接、粗体与斜体格式

Great question! Your existing function does a solid job handling line breaks and links—let’s adjust it to retain bold and italic formatting using markdown-style asterisks, which is clean and readable in email clients.

The Modified Function #

Here’s how to update your htmlToText function to preserve bold (<b>, <strong>) and italic (<i>, <em>) styles:

function htmlToText(html){
 // 移除代码换行符和制表符
 html = html.replace(/\n/g, "");
 html = html.replace(/\t/g, "");

 // 保留粗体格式：替换<b>/<strong>为**...**
 html = html.replace(/<(b|strong)[^>]*>(.*?)<\/\1>/gi, '**$2**');
 // 保留斜体格式：替换<i>/<em>为*...*
 html = html.replace(/<(i|em)[^>]*>(.*?)<\/\1>/gi, '*$2*');

 // 保留HTML换行和制表符
 html = html.replace(/<\/td>/g, "\t");
 html = html.replace(/<\/table>/g, "\n");
 html = html.replace(/<\/tr>/g, "\n");
 html = html.replace(/<\/p>/g, "\n");
 html = html.replace(/<\/div>/g, "\n");
 html = html.replace(/<\/h[1-6]>/g, "\n"); // 修正原h标签正则，匹配合法的h1-h6闭合标签
 html = html.replace(/<br>/g, "\n");
 html = html.replace(/<br( )*\/>/g, "\n");

 // 处理链接格式
 html = html.replace(/<a.*href="(.*?)".*>(.*?)<\/a>/gi, " $2 (Link->$1) ");

 // 将HTML解析为文本
 var dom = (new DOMParser()).parseFromString('<!doctype html><body>' + html, 'text/html');
 return dom.body.textContent;
}

Key Changes Explained #

• Bold/Italic Replacement: We added two regex patterns that match <b>/<strong> and <i>/<em> tags (including any extra attributes like classes or styles) and replace them with markdown-style ** and * respectively. The \1 in the closing tag ensures we match the exact same opening tag (e.g., <strong> closes with </strong>, not </b>).
• Fixed Heading Tag Regex: Your original <\/h> pattern would only match invalid </h> tags—we updated it to <\/h[1-6]> to properly handle valid closing heading tags from </h1> to </h6>.

Test Example #

For your sample content:

这是粗体文本。这是普通文本。这是斜体文本。这是一个链接。

The function will output:

**这是粗体文本。**这是普通文本。*这是斜体文本。* 这是一个链接。 (Link->https://example.com) 

This format keeps your original formatting intent intact while remaining easy to read in plain-text emails.

内容的提问来源于stack exchange，提问作者petoma