Validation Problems..

Hi,

I am trying to validate the email address, username and password in a form i have. I have got it so that it checks to make sure that there is something in the field but i need the email field to check for @ symbol and also i need to make sure that the username and password entries are between 4 and 12 characters.

Here is my code up to now.

function checkform ( form )
{

 if (form.email.value == "") {
    alert( "Please ensure your email addresses have been input correctly e.g. mail@mail.com" );
    form.email.focus();
    return false ;
  }

  if (form.username.value == "") {
    alert( "Please enter a username between 4 - 12 characters" );
    form.username.focus();
    return false ;
  }

  if (form.password.value == "") {
    alert( "Please enter a password between 6 - 12 characters" );
    form.password.focus();
    return false ;
  }

  return true ;
}

Code (markup):

Cheers,
Adam

 

for username:
if (form.username.value.length < 4 || form.username.value.length > 12) { ... }

similarly for password.

for email, if you simply want to check that there's an '@' in the middle of the string:
if (!form.email.value.match(/.+@.+)) { ... }
for more complex email validation, a quick search on your preferred search engine should show you some examples.

 

Thanks for that

It does not seem to be working though, it does not check for these now and just enters without anything entering anything.

 

function checkform ( form )
{


  if (!form.email.value.match(/.+@.+)) {
    alert( "Please ensure your email addresses have been input correctly e.g. mail@mail.com" );
    form.email.focus();
    return false ;
  }

 if (form.username.value.length < 4 || form.username.value.length > 12) {
    alert( "Please enter a username between 4 - 12 characters" );
    form.username.focus();
    return false ;
  }

  if (form.password.value.length < 4 || form.password.value.length > 12) {
    alert( "Please enter a password between 6 - 12 characters" );
    form.password.focus();
    return false ;
  }

  // ** END **
  return true ;
}

Code (markup):

Any ideas?

 

try !form.email.value.match(/^\.+@\.+$/)

for a slightly more advanced e-mail checker..
!form.email.value.match(/^\w+(-\w*)*@[a-zA-Z_]+(\.[a-zA-Z_]+)*\.[a-zA-Z]{2,3}$/)

also, you might want to use regular expressions on your password and username fields as well.. this can make it so you can restrict the characters allowed..

!form.username.value.match(/^\w{4,12}$/)

!form.password.value.match(/^\w{4,12}$/)

these will only allow word characters

 

Sorry, I forgot an ending slash in the email validation.
It's supposed to be:
if (!form.email.value.match(/.+@.+/))

 

Good job in adding the trailing forward slash, but the backslashes in front of the dots shouldn't be there. Otherwise it'd be saying "one or more dots followed by an '@', then followed by one or more dots.

More advanced indeed. Just a few small problems though:
- Email addresses with a dot in it (e.g.: ) would be considered invalid. There are also other valid, non-alphanumeric characters for the part to the left of the '@', which would fail this validation.
- Emails with numbers in the domain name (e.g.: ) would also fail this validation.
- It allows underscores in domain names, but not dashes. It should be the other way around.

But yeah, with a few improvements, this would make a much stricter validation.