PHP中檢查字串是否含有非中文字

function chinese_only($arg_strContent)
{
$blnChineseOnly= true;
$intLoopCount = 0;
$intContentLength = strlen($arg_strContent);
while ($intLoopCount < $intContentLength)
{
$chrSingle = substr($arg_strContent,$intLoopCount,1);
if(ord($chrSingle) > 0x80)
{
$chrSingle = substr($arg_strContent,$intLoopCount,2);
$intLoopCount++;
if(!isBig5($chrSingle))
{
$blnChineseOnly = false;
break;
}
}
else
{
$blnChineseOnly = false;
break;
}
$intLoopCount++;

}
return !$blnChineseOnly;
}
function isBig5($char="")
{
$bc = hexdec(bin2hex($char));
if(($bc>=0xa440 && $bc<= 0xc67e)||($bc>=0xc940 && $bc<= 0xf9dc))
{
return true;
}
else
{
return false;
}
}