php输出验证码怎么弄（php邮箱验证函数）

function checkEmail($email) { // Create the syntactical validation regular expression $regexp = "^([_a-z0-9-] )(\.[_a-z0-9-] )*@([a-z0-9-] )(\.[a-z0-9-] )*(\.[a-z]{2,4})$"; // Presume that the email is invalid $valid = 0; // Validate the syntax if (eregi($regexp, $email)) { list($username,$domaintld) = split("@",$email); // Validate the domain if (getmxrr($domaintld,$mxrecords)) $valid = 1; } else { $valid = 0; } return $valid; }