php截取字符串出现乱码如何解决？

 

//截取字符串，防止出现乱码
function ChgTitle($title)
{
$length = 50; //我们允许字符串显示的最大长度
if (strlen($title)>$length)
{
$temp = 0;
for($i=0; $i<$length; $i++)
{
if (ord($title[$i]) > 128) $temp++;
if ($temp%2 == 0)
$title = substr($title,0,$length)."...";
else
$title = substr($title,0,$length+1)."...";
}
}
return $title;
}