php 格式化電話号碼

隻适用于美國電話号碼

function format_phone($phone) {
    $phone = preg_replace("/[^0-9]/", "", $phone);
    if(strlen($phone) == 7)
        return preg_replace("/([0-9]{3})([0-9]{4})/", "$1-$2", $phone);
    elseif(strlen($phone) == 10)
        return preg_replace("/([0-9]{3})([0-9]{3})([0-9]{4})/","($1) $2-$3",$phone);
    else
        return $phone;
}