JavaScript字符串中有多少字节？
我有一个javascript字符串，当从服务器以UTF-8发送时大约是500K。如何在JavaScript中告诉它的大小？
I have a javascript string which is about 500K when being sent from the server in UTF-8. How can I tell its size in JavaScript?
我知道JavaScript使用UCS-2，所以这意味着每个字符2个字节。但是，它是否依赖于JavaScript实现？或者在页面编码或内容类型？
I know that JavaScript uses UCS-2, so does that mean 2 bytes per character. However, does it depend on the JavaScript implementation? Or on the page encoding or maybe content-type?
字符串根据 ECMA-262第3版规范，值不依赖于实现，每个字符代表一个单个16位单位的UTF-16文本：
String values are not implementation dependent, according the ECMA-262 3rd Edition Specification, each character represents a single 16-bit unit of UTF-16 text:
4.3.16字符串值
4.3.16 String Value
字符串值是String类型的成员，是
有限有序序列，零或
更多16位无符号整数值。
A string value is a member of the type String and is a finite ordered sequence of zero or more 16-bit unsigned integer values.
注意虽然每个值通常为
代表一个16位单位的
UTF-16文本，但该语言不是
的地方任何限制或要求
的值除了它们是
16位无符号整数。
NOTE Although each value usually represents a single 16-bit unit of UTF-16 text, the language does not place any restrictions or requirements on the values except that they be 16-bit unsigned integers.