php检测邮箱密码

$pattern = "/^[0-9a-zA-Z_-]+(\.[0-9a-zA-Z_-]+)*@[a-zA-Z0-9_-]+(\.{1}[a-zA-Z0-9_-]+)*\.{1}[a-zA-Z]{2,4}$/i";
if(!preg_match($pattern,$email)){
echo "邮箱不符合规则";
}
 
//$patternpwd = "/[A-Za-z]{6,15}/";
//$patternpwdnum = "/[0-9]{6,15}/";
$pa="/^(?![0-9]+$)(?![a-zA-Z]+$)[0-9A-Za-z]{6,16}$/";//字母数字不少于6位
if(!preg_match($pa,$pwd)){
    echo "密码不符合规则";
}