这个 HTML 中的 3D 是做什么的？
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What's a 3D doing in this HTML?
提问by Nic
I'm trying to duplicate a mailer I got into my gmail by taking a look at its code. I see a lot of this in multiple source viewers:
我正在尝试通过查看其代码来复制我进入我的 gmail 的邮件程序。我在多个源查看器中看到了很多这样的内容：
<td style=3D"border-bottom: 1px dotted rgb(153,157, 147); border-top: 1px solid rgb(28, 140, 78);" width=3D"90">=A0</td>
<td style=3D"border-bottom: 1px dotted rgb(153,157, 147); border-top: 1px solid rgb(28, 140, 78);" align=3D"right" width=3D"110">
Is 3D some sort of mail rendering thing I don't know about?
3D 是某种我不知道的邮件渲染吗？
回答by Chris Jester-Young
It's an email encoding system called "quoted-printable", which allows non-ASCII characters to be represented as ASCII for email transportation.
它是一种名为“ quoted-printable”的电子邮件编码系统，它允许将非 ASCII 字符表示为 ASCII 以进行电子邮件传输。
In quoted-printable, any non-standard email octets are represented as an =sign followed by two hex digits representing the octet's value. Of course, to represent a plain =in email, it needs to be represented using quoted-printable encoding too: 3D are the hex digits corresponding to ='s ASCII value (61).
在quoted-printable 中，任何非标准电子邮件八位字节都表示为一个=符号，后跟两个表示八位字节值的十六进制数字。当然，要=在电子邮件中表示纯=文本，也需要使用带引号的可打印编码来表示：3D 是对应于ASCII 值 (61)的十六进制数字。
