Method 1：
function hidtel($phone){
????$IsWhat = preg_match('/(0[0-9]{2,3}[\-]?[2-9][0-9]{6,7}[\-]?[0-9]?)/i',$phone); //固定德律風
????if($IsWhat == 1){
????????return preg_replace('/(0[0-9]{2,3}[\-]?[2-9])[0-9]{3,4}([0-9]{3}[\-]?[0-9]?)/i','$1****$2',$phone);
????}else{
????????return??preg_replace('/(1[358]{1}[0-9])[0-9]{4}([0-9]{4})/i','$1****$2',$phone);
????}
}

PHP編程Method 2：
$num = "13966778888"
$str = substr_replace($num,'****',3,4);

$phonenum = "13966778888";
echo hidtel($phonenum);