用ASP判断Email地址是否有效

用asp判断email地址是否有效

2000-03-23· 王俊·cpcw

　　在用asp编写页面时，如果涉及到邮件发送，一般会要求输入email地址。错误的email地址往往带来许多不必要的麻烦，用下面的函数isvalidemail就能判断出一个email地址是否有效。

函数源代码：

<%

function isvalidemail(email)

validflag = false

if (email <> "") and (instr(1, email, "@") > 0) and (instr(1, email, ".") > 0) then

atcount = 0

specialflag = false

for atloop = 1 to len(email)

atchr = mid(email, atloop, 1)

if atchr = "@" then atcount = atcount + 1

if (atchr >= chr(32)) and (atchr <= chr(44)) then specialflag = true

if (atchr = chr(47)) or (atchr = chr(96)) or (atchr >= chr(123)) then specialflag = true

if (atchr >= chr(58)) and (atchr <= chr(63)) then specialflag = true

if (atchr >= chr(91)) and (atchr <= chr(94)) then specialflag = true

next

if (atcount = 1) and (specialflag = false) then

badflag = false

tary1 = split(email, "@")

username = tary1(0)

domainname = tary1(1)

if (username = "") or (domainname = "") then badflag = true

if mid(domainname, 1, 1) = "." then badflag = true

if mid(domainname, len(domainname), 1) = "." then badflag = true

validflag = true

end if

end if

if badflag = true then validflag = false

isvalidemail = validflag

end function

%>

用法举例：

isvalidemail("my_263_email@263.net") 返回ture

isvalidemail("zh99wj@tonghua.com.cn") 返回ture

isvalidemail("myemail263.net") 返回false

isvalidemail("my_263_email@263) 返回false

请注意，函数只是判断email地址格式是否有效，但并不能检查该地址是否确实存在。