Javascript-Check if a string has fullstop

[hakermania]

Hi, this doesn't work:

<script type="text/javascript">
function givemail()
{
r=prompt("Give me your e-mail address please:");
if (r.length < 4)
{
document.write("Small Address!");
}
else if (r.match("@") != "@")
{
document.write("@ not found!");
}
else if (r.match(".") != ".")
{
document.write("There is no fullstop!!!");
}
else
{
document.write("Check the inbox at your email address: " + r);
}
}
</script>
The @ check works fine but even if the mail address has a fullstop the result is

document.write("There is no fullstop!!!");
Any help on how to tell the program for the fullstop?

[soltanis]

The function you are using matches regular expressions, not strings. In RegExp parlance the "." character matches any non-newline character, which means it matches the first character in your string more likely than not.

EDIT:
See below for correct ways of doing things.

[Compyx]

Email addresses rather complex little critters, here's a regular expression in Perl to validate an e-mail address:
http://www.ex-parrot.com/pdw/Mail-RFC822-Address.html

If I just wanted to check if a string had a full stop in it, I'd do something like:


if (s.indexOf('.') >= 0) {
// found full stop
}

a regex is a bit overkill for such a task.

[hakermania]

The function you are using matches regular expressions, not strings. In RegExp parlance the "." character matches any non-newline character, which means it matches the first character in your string more likely than not.

Instead to match a literal . you should escape the metacharacter to tell the parser you mean the literal character.



r.match("\.")
If you are trying to match an email address (it looks like you are?) you can combine the whole thing into a more complex regular expression:



r.match("[a-zA-Z0-9._]@\w\.\w")
My regular expressions are rusty from too much Python so a Perl hacker can probably jump in and improve/fix this.
Ok thank you. I am not afraid of hacker attacks because in the site I am currently building there is no credit card numbers or something like that.It's just a unix scripting tutorial on Greek :P

[Hellkeepa]

HELLo!

Missing a + after the closing square bracket and the two word character matches, to make it match more than just one character. Other than that, you're also missing the ^ and $ anchors, to make sure it matches the entire string.

For a more complete check, I recommend having a look at the RegExp in my "val_Email ()" function: http://norskwebforum.no/pastebin/7609

Happy codin'!

[roccivic]

Validation of email addresses must be done on the server-side! If you already have that implemented and just want to save yourself some unnecessary traffic, then fair enough.

Here's a proper way for validating email addresses (in PHP, but should be easy enough to port to JS):


<?php
/*

Taken from: http://www.linuxjournal.com/article/9585

Validate an email address.
Provide email address (raw input)
Returns true if the email address has the email
address format and the domain exists.
*/

function validEmail($email) {

// list of domains that are not allowed
$banlist = array( "placella.com",
"ratethatpage.com" );

$isValid = true;
$atIndex = strrpos($email, "@");
if (is_bool($atIndex) && !$atIndex) {
$isValid = false;
}
else {
$domain = substr($email, $atIndex+1);
$local = substr($email, 0, $atIndex);
$localLen = strlen($local);
$domainLen = strlen($domain);
if ( in_array($domain, $banlist) ) {
// banned domain
$isValid = false;
}
else if ($localLen < 1 || $localLen > 64) {
// local part length exceeded
$isValid = false;
}
else if ($domainLen < 1 || $domainLen > 255) {
// domain part length exceeded
$isValid = false;
}
else if ($local[0] == '.' || $local[$localLen-1] == '.') {
// local part starts or ends with '.'
$isValid = false;
}
else if ($domain[$domainLen-1] == '.') {
// domain part ends with '.'
$isValid = false;
}
else if (preg_match('/\\.\\./', $local)) {
// local part has two consecutive dots
$isValid = false;
}
else if (!preg_match('/^[A-Za-z0-9\\-\\.]+$/', $domain)) {
// character not valid in domain part
$isValid = false;
}
else if (!preg_match('/\\./', $domain)) {
// domain has no dots
$isValid = false;
}
else if (preg_match('/\\.\\./', $domain)) {
// domain part has two consecutive dots
$isValid = false;
}
else if (!preg_match('/^(\\\\.|[A-Za-z0-9!#%&`_=\\/$\'*+?^{}|~.-])+$/', str_replace("\\\\","",$local))) {
// character not valid in local part unless
// local part is quoted
if (!preg_match('/^"(\\\\"|[^"])+"$/', str_replace("\\\\","",$local))) {
$isValid = false;
}
}
/* if ($isValid && !(checkdnsrr($domain,"MX") || checkdnsrr($domain,"A"))) {
// domain not found in DNS
$isValid = false;
}*/
}
return $isValid;
}
?>

[hakermania]

Guys............:(

<script type="text/javascript">
function givemail()
{
r=prompt("Give me your e-mail address please:");
if (r.length < 4)
{
document.write("Small address.");
}
else if (r.match("@") != "@")
{
document.write("NO @");
}
else if (r.match("\.") != ".")
{
document.write("No fullstop");
}
else
{
document.write("Check inbox of " + r);
}
}
</script>
Still No fullstop message :'(

[roccivic]

match takes a RegExp as it's argument. You'll have do something along the lines of:


foo = new RegExp(pattern, modifiers);
r.match(foo);

See here: http://www.w3schools.com/jsref/jsref_match.asp

[myrtle1908]

Guys............:(
Still No fullstop message :'(


var s = prompt('Enter some text');
if (/\./g.test(s)) {
alert('Fullstop found.');
} else {
alert('No fullstop.');
}

[soltanis]

Or use the indexOf trick.

Sorry, it has been a long time since I have used either JS or Perl regular expressions. Too much Python/C in me.