以下代碼試用于GB2312編碼，截取中文字符串是PHP中一個(gè)頭疼的問(wèn)題，解決方法是根據(jù)值是否大于等于128來(lái)判斷是否是雙字節(jié)字符，以避免出現(xiàn)亂碼的情況。但中英文混合、特殊符號(hào)等問(wèn)題總是存在，現(xiàn)在寫(xiě)一個(gè)比較全面的，僅供參考：

程序說(shuō)明：1. len 參數(shù)以中文字符為標(biāo)準(zhǔn)，1len等于2個(gè)英文字符，為了形式上好看些2. 如果將magic參數(shù)設(shè)為false，則中文和英文同等看待，取絕對(duì)的字符數(shù)3. 特別適用于用htmlspecialchars()進(jìn)行過(guò)編碼的字符串4. 能正確處理GB2312中實(shí)體字符模式（𖰰）

程序代碼：

function FSubstr($title,$start,$len='',$magic=true) {/** *; powered by Smartpig *; mailto:d.einstein@263.net */ $length = 0;if($len == '') $len = strlen($title);

//判斷起始為不正確位置if($start > 0){ $cnum = 0; for($i=0;$i<$start;$i++) { if(ord(substr($title,$i,1)) >= 128) $cnum ++; } if($cnum%2 != 0) $start--; unset($cnum);}

if(strlen($title)<=$len) return substr($title,$start,$len);

$alen= 0;$blen = 0;

$realnum = 0;

for($i=$start;$i<strlen($title);$i++){ $ctype = 0; $cstep = 0; $cur = substr($title,$i,1); if($cur == '&') { if(substr($title,$i,4) == '&lt;') { $cstep = 4; $length += 4; $i += 3; $realnum ++; if($magic) { $alen ++; } } else if(substr($title,$i,4) == '&gt;') { $cstep = 4; $length += 4; $i += 3; $realnum ++; if($magic) { $alen ++; } } else if(substr($title,$i,5) == '&amp;') { $cstep = 5; $length += 5; $i += 4; $realnum ++; if($magic) { $alen ++; } } else if(substr($title,$i,6) == '&quot;') { $cstep = 6; $length += 6; $i += 5; $realnum ++; if($magic) { $alen ++; } } else if(substr($title,$i,6) == '&#039;') { $cstep = 6; $length += 6; $i += 5; $realnum ++; if($magic) { $alen ++; } } else if(preg_match('/&#(d+);/i',substr($title,$i,8),$match)) { $cstep = strlen($match[0]); $length += strlen($match[0]); $i += strlen($match[0])-1; $realnum ++; if($magic) { $blen ++; $ctype = 1; } } }else{ if(ord($cur)>=128) { $cstep = 2; $length += 2; $i += 1; $realnum ++; if($magic) { $blen ++; $ctype = 1; } }else{ $cstep = 1; $length +=1; $realnum ++; if($magic) { if(ord($cur) >= 65 && ord($cur) <= 90) { $blen++; }else{ $alen++; } } } } if($magic) { if(($blen*2+$alen) == ($len*2)) break; if(($blen*2+$alen) == ($len*2+1)) { if($ctype == 1) { $length -= $cstep; break; }else{ break; } } }else{ if($realnum == $len) break; }}

unset($cur);unset($alen);unset($blen);unset($realnum);unset($ctype);unset($cstep);

return substr($title,$start,$length);}

呵呵，一會(huì)兒把UTF-8編碼下的代碼也貼出來(lái)