转载自http://www.kalvin.cn/?action=show&id=239

[code]<?
function uni_decode($s) {
preg_match_all('/\&\#([0-9]{2,5})\;/', $s, $html_uni);
preg_match_all('/[\\\%]u([0-9a-f]{4})/ie', $s, $js_uni);
$source = array_merge($html_uni[0], $js_uni[0]);
$js = array();
for($i=0;$i<count($js_uni[1]);$i++) {
$js[] = hexdec($js_uni[1][$i]);
}
$utf8 = array_merge($html_uni[1], $js);
$code = $s;
for($j=0;$j<count($utf8);$j++) {
$code = str_replace($source[$j], unicode2utf8($utf8[$j]), $code);
}
return $code;//$s;//preg_replace('/\\\u([0-9a-f]{4})/ie', "chr(hexdec('\\1'))", $s);
}

function unicode2utf8($c) {
$str="";
if ($c < 0x80) {
$str.=chr($c);
} else if ($c < 0x800) {
$str.=chr(0xc0 | $c>>6);
$str.=chr(0x80 | $c & 0x3f);
} else if ($c < 0x10000) {
$str.=chr(0xe0 | $c>>12);
$str.=chr(0x80 | $c>>6 & 0x3f);
$str.=chr(0x80 | $c & 0x3f);
} else if ($c < 0x200000) {
$str.=chr(0xf0 | $c>>18);
$str.=chr(0x80 | $c>>12 & 0x3f);
$str.=chr(0x80 | $c>>6 & 0x3f);
$str.=chr(0x80 | $c & 0x3f);
}
return $str;
}

$str='%u5927%u5BB6%u597D%uFF0C我是孤魂！<br />\u8FD9\u662F\u6D4B\u8BD5\u6587\u672C\uFF01';
echo uni_decode($str); // 大家好，我是孤魂！这是测试文本！
?> [/code]