考虑一下你是否有这样的标题:

content-encoding: gzip
content-length: 52098
content-type: text/javascript; charset=UTF-8

内容长度是压缩消息体的大小，以“八位”为单位(即以8位为单位，这恰好是所有现代计算机的“字节”)。

实际消息体的大小可以是其他大小，可能是150280字节。

字符的数量也可以不同，可能是150231个字符，因为一些unicode字符使用多个字节(注意UTF-8是一种标准编码)。

所以，不同的数字取决于你是否关心有多少数据被传输，或者有多少数据被保存，或者有多少符号被看到。当然，不能保证会提供这些头文件。

从本页

The most common use of POST, by far, is to submit HTML form data to CGI scripts. In this case, the Content-Type: header is usually application/x-www-form-urlencoded, and the Content-Length: header gives the length of the URL-encoded form data (here's a note on URL-encoding). The CGI script receives the message body through STDIN, and decodes it. Here's a typical form submission, using POST: POST /path/script.cgi HTTP/1.0 From: frog@jmarshall.com User-Agent: HTTPTool/1.0 Content-Type: application/x-www-form-urlencoded Content-Length: 32

根据说明书:

The Content-Length entity-header field indicates the size of the entity-body, in decimal number of OCTETs, sent to the recipient or, in the case of the HEAD method, the size of the entity-body that would have been sent had the request been a GET. Content-Length = "Content-Length" ":" 1*DIGIT An example is Content-Length: 3495 Applications SHOULD use this field to indicate the transfer-length of the message-body, unless this is prohibited by the rules in section 4.4. Any Content-Length greater than or equal to zero is a valid value. Section 4.4 describes how to determine the length of a message-body if a Content-Length is not given. Note that the meaning of this field is significantly different from the corresponding definition in MIME, where it is an optional field used within the "message/external-body" content-type. In HTTP, it SHOULD be sent whenever the message's length can be determined prior to being transferred, unless this is prohibited by the rules in section 4.4.

从这里开始:

The Content-Length entity-header field indicates the size of the entity-body, in decimal number of OCTETs, sent to the recipient or, in the case of the HEAD method, the size of the entity-body that would have been sent had the request been a GET. Content-Length = "Content-Length" ":" 1*DIGIT An example is Content-Length: 3495 Applications SHOULD use this field to indicate the transfer-length of the message-body, unless this is prohibited by the rules in section 4.4. Any Content-Length greater than or equal to zero is a valid value. Section 4.4 describes how to determine the length of a message-body if a Content-Length is not given. Note that the meaning of this field is significantly different from the corresponding definition in MIME, where it is an optional field used within the "message/external-body" content-type. In HTTP, it SHOULD be sent whenever the message's length can be determined prior to being transferred, unless this is prohibited by the rules in section 4.4.

我的解释是，这意味着“导线上”的长度，即“编码”内容的长度

一个八位是8位。Content-length是消息体所代表的字节数。

考虑一下你是否有这样的标题:

content-encoding: gzip
content-length: 52098
content-type: text/javascript; charset=UTF-8

内容长度是压缩消息体的大小，以“八位”为单位(即以8位为单位，这恰好是所有现代计算机的“字节”)。

实际消息体的大小可以是其他大小，可能是150280字节。

字符的数量也可以不同，可能是150231个字符，因为一些unicode字符使用多个字节(注意UTF-8是一种标准编码)。

所以，不同的数字取决于你是否关心有多少数据被传输，或者有多少数据被保存，或者有多少符号被看到。当然，不能保证会提供这些头文件。