I've got this mailing list app (php/mysql) that I'm working into my website and I've got it up and running and now I'm trying to make a couple modifications to the existing code.

As far as I understand the code, when someone submits an email address via the <form> tag, the script runs a javascript to check whether the email addres is composed of valid characters or if it's already in the database before processing the submission. What I want to do is configure the script so that upon a successful submission an alert box pops up with a little "thank you" message (or whatever, you get the idea ).

The existing code already throws up an alert box if the email address' format is invalid. I think the code is in here that I want to mess with, but I'm not sure where exact because I don't really know javascript.

           <script language=JavaScript type=text/javascript>
function checkNEmail(form) {
    if (isBlank(form.email.value) || isBlank(form.name.value) || !isEmailValid(form.email.value) ) 
    {
        alert("Please enter a valid Name and  Email Address .\nThe email or name you have typed in does not appear to be valid.");
        form.email.focus();
        return false;
    }
    }

function checkEmail(form) {
    if (isBlank(form.email.value) || !isEmailValid(form.email.value) ) {
        alert("Please enter a valid Email Address.\nThe email you have typed in does not appear to be valid.");
        form.email.focus();
        return false;
    }
return true;

}

function isBlank(fieldValue) {
    var blankSpaces = / /g;
    fieldValue = fieldValue.replace(blankSpaces, "");
    return (fieldValue == "") ? true : false;
}

function isEmailValid(fieldValue) {
    var emailFilter = /^.+@.+\..{2,4}$/;
    var atSignFound = 0;
    for (var i = 0; i <= fieldValue.length; i++)
        if ( fieldValue.charAt(i) == "@" )
            atSignFound++;
    if ( atSignFound > 1 )
        return false;
    else
        return ( emailFilter.test(fieldValue) && !doesEmailHaveInvalidChar(fieldValue) ) ? true : false;
}

function doesEmailHaveInvalidChar(fieldValue) {
    var illegalChars = /[\(\)\<\>\,\;\:\\\/\"\[\] ]/;
    return ( illegalChars.test(fieldValue) ) ? true : false;
}
</script>

I'm not sure if this next part helps at all, but if the email turns out valid and is not already in the database, then it seems that the file email_not_exist.php is called which contains this:

 <table width="100%" border="0" cellspacing="0" cellpadding="0">
  <tr> 
    <td width="38%"><div align="center">Removal Error !!!</div></td>
  </tr>
  <tr> 
    <td>&nbsp;</td>
  </tr>
  <tr> 
    <td><div align="center"> <?php echo str_replace("{email}",$email,$lang_emailexist_adress_error); ?></div></td>
  </tr>
  <tr> 
    <td>&nbsp;</td>
  </tr>
</table>

Thanks a lot for any ideas you all might have and I'm happy to give any more information that might help.

Just change your function checkEmail() to this:

function checkEmail(form) {
    if (isBlank(form.email.value) || !isEmailValid(form.email.value) ) {
        alert("Please enter a valid Email Address.\nThe email you have typed in does not appear to be valid.");
        form.email.focus();
        return false;
    }
    else {
        alert("Thank you!");
        return true;
    }
}

Thank you soooo much Oneway. I've posted in a ton of forums and so far everyone just keeps saying, "why don't you do this instead, or why have it reload on the same page, or why are you using so many <div>s..." If I coded then script myself I wouldn't be asking this question in the first place. I get they're trying to be helpful in their own ways but I just want to get the site done

Thanks again man, that totally did it.

Actually, I did have a follow up question: Is there any other popup that can be used in this instance since I just noticed that the "alert" with the "!" icon doesn't exactly instill a sense of calm when I'm trying to "thank" someone. Something along the lines of the little alert window without the caution symbol?

Let's see... There are confirm("message"); and prompt("message"); but those aren't really meant for just displaying a message.

Another option is to fake an alertbox by creating some html that looks like an alert box (which you can then customise to not show the exclamation mark.) I seem to remeber a good tutorial about it, but i can't find it anymore. You'll have to search on google a bit more than i did.
i used (javascript custom alert box) as keywords.

Awesome, thanks for the lead! I'll see what I can turn up.