对于url编码一般出现在服务器端和客户端两个地方，我们的服务器端使用PHP脚本语言；而客户端一般是浏览器，这里就谈js的url编码；
关于PHP的urlencode与rawurlencode的比较：
<?php
for ($i = 0x20; $i < 0x7f; $i++) {
$str .= dechex($i);
}
$asscii = pack("H*",$str);
echo "所有的可打印的asscii字符：（从空格到~）n". $asscii."\n";
echo "urlencode 的结果：\n".urlencode($asscii);
echo "\n";
echo "urlencode 不做编码的字符：\n".preg_replace("/%.{2}/","",urlencode($asscii));
echo "\n";
echo "rawurlencode 的结果：\n".rawurlencode($asscii);
echo "\n";
echo "rawurlencode 不做编码的字符：\n".preg_replace("/%.{2}/","",rawurlencode($asscii));
echo "\n";
exit;
?>
输出结果：
———————————————————————————
所有的可打印的asscii字符：（从空格到~）
!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_abcdefghijklmnopqrstuvwxyz{|}~
urlencode 的结果：
+%21%22%23%24%25%26%27%28%29%2A%2B%2C-.%2F0123456789%3A%3B%3C%3D%3E%3F%40ABCDEFGHIJKLMNOPQRSTUVWXYZ%5B%5C%5D%5E_%60abcdefghijklmnopqrstuvwxyz%7B%7C%7D%7E
urlencode 不做编码的字符：
+-.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
rawurlencode 的结果：
%20%21%22%23%24%25%26%27%28%29%2A%2B%2C-.%2F0123456789%3A%3B%3C%3D%3E%3F%40ABCDEFGHIJKLMNOPQRSTUVWXYZ%5B%5C%5D%5E_%60abcdefghijklmnopqrstuvwxyz%7B%7C%7D%7E
rawurlencode 不做编码的字符：
-.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
---------------------------------------------------------------------------------
比较二者的结果：
1. 数字、大小写字母都不编码
2. 减号、点号、下划线 三个不编码
3. rawurlencode比urlencode多编码一个”加号“
关于JavaScript中escape与encodeURIComponent的区别：
>>> console.log(encodeURIComponent("统一注册1"));
%E7%BB%9F%E4%B8%80%E6%B3%A8%E5%86%8C1
>>> console.log(escape("统一注册1"));
%u7EDF%u4E00%u6CE8%u518C1
<?php
echo iconv("utf-8","gbk",urldecode("%E7%BB%9F%E4%B8%80%E6%B3%A8%E5%86%8C1"));
echo "\n";
echo urldecode("%u7EDF%u4E00%u6CE8%u518C1");
// 使用下面的unescape可以
//echo iconv("utf-8","gbk",unescape("%u7EDF%u4E00%u6CE8%u518C1"); exit;
?>
输出结果：
======================================统一注册1
%u7EDF%u4E00%u6CE8%u518C1
======================================
结果说明：
1. encodeURIComponent 总是把输入转换成utf8编码处理的，按字节编码
2. escape是按照unicode编码处理的，因为它也对url中不安全的字符做了编码，所以也可以在url中做编码使用，但是，服务器端不会自动解码，下面提供一个PHP版的解码函数，是用手册里找的：
<?php
function unescape($str) {
$str = rawurldecode($str);
preg_match_all("/(?:%u.{4})|&#x.{4};|&#d+;|.+/U",$str,$r);
$ar = $r[0];
foreach($ar as $k=>$v) {
if(substr($v,0,2) == "%u")
$ar[$k] = iconv("UCS-2","UTF-8",pack("H4",substr($v,-4)));
elseif(substr($v,0,3) == "&#x")
$ar[$k] = iconv("UCS-2","UTF-8",pack("H4",substr($v,3,-1)));
elseif(substr($v,0,2) == "&#") {
$ar[$k] = iconv("UCS-2","UTF-8",pack("n",substr($v,2,-1)));
}
}
return join("",$ar);
}
?>
>>> console.log(escape(" !\"#$%&'()*+,-./0123456789:;=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_abcdefghijklmnopqrstuvwxyz{|}~"));
%20%21%22%23%24%25%26%27%28%29*+%2C-./0123456789%3A%3B%3C%3D%3E%3F@ABCDEFGHIJKLMNOPQRSTUVWXYZ%5B%5D%5E_%60abcdefghijklmnopqrstuvwxyz%7B%7C%7D%7E
>>> console.log(encodeURIComponent("!\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_abcdefghijklmnopqrstuvwxyz{|}~"));
%20!%22%23%24%25%26'()*%2B%2C-.%2F0123456789%3A%3B%3C%3D%3E%3F%40ABCDEFGHIJKLMNOPQRSTUVWXYZ%5B%5D%5E_%60abcdefghijklmnopqrstuvwxyz%7B%7C%7D~
>>> console.log(escape("!\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_abcdefghijklmnopqrstuvwxyz{|}~").replace(/%.{2}/g,""));
*+-./0123456789@ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz
>>> console.log(encodeURIComponent("!\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~").replace(/%.{2}/g,""));
!'()*-.0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz~
结果比较：
escape未编码的字符： *+-./@_ 共7个
encodeURIComponent未编码的字符： !'()*-._~ 共9个