javascript中存在几种对URL字符串进行编码的方法：escape()，encodeURI()，以及encodeURIComponent()
。这几种编码所起的作用各不相同。
escape() 方法：
采用ISO Latin字符集对指定的字符串进行编码。所有的空格符、标点符号、特殊字符以及其他非ASCII字符
都将被转化成%xx格式的字符编码（xx等于该字符在字符集表里面的编码的16进制数字
）。比如，空格符对应的编码是%20。
英文解释：MSDN JScript Reference: 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."
Edge Core Javascript Guide: 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.
针对非ASCII字符
第一步 就是你是某种字符（gbk/utf-8），
第二部 将这种字符的（gbk/utf-8）得到unicode 的 16进制的字节码
第三部 将这些字节码进行url编码
不会被此方法编码的字符： @ * / +
encodeURI() 方法：
把URI字符串采用UTF-8编码格式转化成escape格式的字符串。
不会被此方法编码的字符：! @ # $& * ( ) = : / ; ? + '
英文解释：MSDN JScript Reference: 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. Edge Core Javascript Guide: 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
针对非ASCII字符
第一步 就是你是某种字符（gbk/utf-8），
第二部 将这种字符的（gbk/utf-8）得到utf-8的 16进制的字节码
第三部 将这些字节码进行url编码
encodeURIComponent() 方法：
把
URI字符串采用UTF-8编码格式转化成escape格式的字符串。
与encodeURI()相比，这个方法将对更多的字符进行编码，比如 /
等字符。所以如果字符串里面包含了URI的几个部分的话
，不能用这个方法来进行编码，否则 / 字符被编码之后URL将显示错误。
针对非ASCII字符
第一步 就是你是某种字符（gbk/utf-8），
第二部 将这种字符的（gbk/utf-8）得到utf-8的 16进制的字节码
第三部 将这些字节码进行url编码
不会被此方法编码的字符：! * ( ) '
英文解释：MSDN JScript Reference: 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. Mozilla Developer Core Javascript Guide： 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.
因
此，对于中文字符串来说，如果不希望把字符串编码格式转化成UTF-8格式的（比如原页面和目标页面的charset是一致的时候），只需要使用
escape
。如果你的页面是GB2312或者其他的编码，而接受参数的页面是UTF-8编码的，就要采用encodeURI或者
encodeURIComponent。
另外，encodeURI/encodeURIComponent是在javascript1.5之后引进的，escape则在javascript1.0版本就有。
英文注释：The escape() method does not encode the + character which is
interpreted as a space on the server side as well as generated by forms
with spaces in their fields. Due to this shortcoming, you should avoid
use of escape() whenever possible. The best alternative is usually
encodeURIComponent().Use of the encodeURI() method is a bit more
specialized than escape() in that it encodes for URIs [REF] as opposed
to the querystring, which is part of a URL. Use this method when you
need to encode a string to be used for any resource that uses URIs and
needs certain characters to remain un-encoded. Note that this method
does not encode the ' character, as it is a valid character within
URIs.Lastly, the encodeURIComponent() method should be used in most
cases when encoding a single component of a URI. This method will encode
certain chars that would normally be recognized as special chars for
URIs so that many components may be included. Note that this method does
not encode the ' character, as it is a valid character within URIs.