The difference between escape, encodeURI and encodeURIComponent_javascript skills

escape() 方法

MSDN JScript Reference中如是说：

The escape method returns a string value (in Unicode format) that contains the contents of [the argument]. All spaces, punctuation, accented characters, and any other non-ASCII characters are replaced with %xx encoding, where xx is equivalent to the hexadecimal number representing the character. For example, a space is returned as "%20."

鄙人译：escape方法以Unicode格式返回一个包含传入参数内容的string类型的值。 Escape方法会将传入参数中所有的空格、标点符号、重音字符以及其它任何非ASCII字符替换为%xx的编码形式，其中xx与其所表示的字符的16进制数表示形式相同。如空格字符的16进制表示形式为0x20，则此时xx应为20，即escape(‘ ') 返回“%20”。

Mozilla Developer Core Javascript Guide中如是说：

The escape and unescape functions let you encode and decode strings. The escape function returns the hexadecimal encoding of an argument in the ISO Latin character set. The unescape function returns the ASCII string for the specified hexadecimal encoding value.

鄙人译：escape和unescape方法能够帮助你编码和解码字符串。escape方法对于ISO Latin字符集中的字符组成的参数，返回其16进制编码。相对应的，unescape方法则能将16进制编码形式的参数转化成为其ASCII码形式。

encodeURI()方法

MSDN JScript Reference中如是说：

The encodeURI method returns an encoded URI. If you pass the result to decodeURI, the original string is returned. The encodeURI method does not encode the following characters: ":", "/", ";", and "?". Use encodeURIComponent to encode these characters.

鄙人译：encodeURI方法返回一个经过编码的URI。如果将encodeURI方法的编码结果传递给decodeURI方法作参数，则能得到原始的未编码的字符串。需要注意到是encodeURI方法不编码如下字符":", "/", ";", and "?"。如果想要编码这些字符，请使用encodeURIComponent方法。

Mozilla Developer Core Javascript Guide中如是说：

Encodes a Uniform Resource Identifier (URI) by replacing each instance of certain characters by one, two, or three escape sequences representing the UTF-8 encoding of the character.

鄙人译：通过将每个属于特定的字符集合的字符替换为一个、两个或者三个（为什么是“一个、两个或者三个”本人也没有搞懂，望高人赐教）使用UTF-8编码来表示这个字符的escape序列来编码一个URI。如 ~!@#$%^&*(){}[]=:/,;?+\'"\\ 将被替换为 ~!@#$%25%5E&*()%7B%7D%5B%5D=:/,;?+'%22%5C

encodeURIComponent()方法

MSDN JScript Reference中如是说：

The encodeURIComponent method returns an encoded URI. If you pass the result to decodeURIComponent, the original string is returned. Because the encodeURIComponent method encodes all characters, be careful if the string represents a path such as /folder1/folder2/default.html. The slash characters will be encoded and will not be valid if sent as a request to a web server. Use the encodeURI method if the string contains more than a single URI component.

鄙人译：encodeURIComponent方法返回一个编码过的URI。如果将encodeURIComponent方法的编码结果传递给encodeURIComponent方法作参数，则能得到原始的未编码的字符串。因为encodeURIComponent方法会编码所有的字符，所以如果待编码的字符串是用来表示一个路径（如/dir1/dir2/index.htm）时，就一定要小心使用了。‘/'符号会被其编码之后，将不再是一个有效的路径标识符，所以不能被web服务器正确地识别。当字符串包含一个单独的URI component(指?后面的请求参数)的时候，请使用此方法。

Mozilla Developer Core Javascript Guide中如是说：

Encodes a Uniform Resource Identifier (URI) component by replacing each instance of certain characters by one, two, or three escape sequences representing the UTF-8 encoding of the character.

鄙人译：通过将每个属于特定的字符集合的字符替换为一个、两个或者三个（为什么是“一个、两个或者三个”本人也没有搞懂，望高人赐教）使用UTF-8编码来表示这个字符的escape序列来编码一个URIComponent。

有什么区别？何时使用？

通过上面的介绍可以看出，MS的文档明显要比Mozilla详细、易懂一些，但是它们表达的都是一个意思。但是escape(), encodeURI()和 encodeURIComponent()有什么异同，它们分别适用于那种特定的情况呢？

The escape method does not encode characters. And we know that in the form fields submitted by the user, if there are spaces, they will be converted into characters, and when the server parses, the characters will be considered to represent spaces. Due to this flaw, the escape method does not handle all non-ASCII characters correctly. You should try to avoid using the escape method. Instead, you'd better choose the encodeURIComponent() method.

Characters not encoded by escape(): @*/

Compared with using the escape method, using the encodeURI method will appear more professional. You can use this method when you need to encode an entire URI, because the legal characters in the URI will not be encoded. It should be noted that the character ' is also a legal character in the URI, so it will not be encoded.

encodeURI() does not encode characters: ~!@#@{content}*()=:/,;? '

The encodeURIComponent method should be the most commonly used when encoding a single URIComponent (referring to request parameters). It should be noted that the character ' is also a legal character in the URI, so it will not be encoded.

Characters not encoded by encodeURIComponent(): ~!*()'