I have to build a small contactform validator in JS, which checks the fields' values when submit is clicked. I am experiencing problems with getting the email validation to work properly. This is what I've got:

function validate_form()
{
    valid = true;

	// Validation of email input
	if ( (document.contact.email.length < 7) || (document.contact.email.value == "") || (!document.contact.email.indexOf("@")) || (!document.contact.email.indexOf(".")) )
	{
		alert("Please fill in a correct email address.");
		valid = false;
	}
    return valid;
}

When I don't fill in anything in the email field, I indeed get the proper alert. But when I fill in a string between 1 and 7 characters, the (document.contact.email.length < 7) is not met. The same goes for the last two conditions: (!document.contact.email.indexOf("@")) || (!document.contact.email.indexOf(".")). Even when (one of) these two conditions are not met, it is possible to submit the form...

Does anybody know what I am doing wrong? I am new with developing and especially with JS so please go a little bit easy on me. :)

Thanks!

Please paste the html form you use to call this function. Thanks.

Please paste the html form you use to call this function. Thanks.

Hey, thanks for asking!

Here is the contact-form as-is. Please note it is in the Dutch language, so sorry if you don't understand some field-names. Also, the above mentioned javascript is included in <script type="text/javascript"></script> tags.

<form enctype="multipart/form-data" action="submitform.php" method="post" name="contact" onsubmit="return validate_form();">
<fieldset>
<legend><h1>Contact</h1></legend>
	<table class="contact">
		<tr>
			<td class="contactLabel"><label for="aanhef"><b>Aanhef </b>*</label></td>
			<td><input type="radio" name="aanhef" id="aanhef" value="De heer" />De heer&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input type="radio" name="aanhef" id="aanhef" value="Mevrouw" />Mevrouw&nbsp;&nbsp;&nbsp;<!-- Validation! !--></td>
		</tr>
		<tr>
			<td class="contactLabel"><label for="naam"><b>Naam </b>*</label></td>
			<td><input type="text" name="naam" id="naam" /><!-- Validation! !--></td>
		</tr>
		<tr>
			<td class="contactLabel"><label for="email"><b>E-mailadres </b>*</label></td>
			<td><input type="text" name="email" id="email" /><!-- Validation! !--></td>
		</tr>
		<tr>
			<td class="contactLabel"><label for="telefoon"><b>Landcode </b>*</label></td>
			<td><input type="text" name="landcode" id="landcode" maxlength="3" size="3" /> <b> Telefoonnummer </b>*<input type="text" name="telefoon" id="telefoonnummer" maxlength="11" size="12" /><!-- Validation! !--></td>
		</tr>
		<tr>
			<td class="contactLabel"><label for="onderwerp"><b>Onderwerp </b>*</label></td>
			<td>
					<select name="onderwerp">
						<option value="domains">Domeinregistraties</option>
						<option value="support">Support / Helpdesk</option>
						<option value="sales">Verkoopassistentie</option>
						<option value="admin">Administratie</option>
					</select>
			</td>
		<tr>
			<td class="contactLabelVraag"><label for="vraag"><b>Uw vraag </b>*</label></td>
			<td><textarea name="vraag" id="vraag" rows="6" cols="30"></textarea><!-- Validation! !--></td>
		</tr>
		<tr>
			<td class="contactLabel"><label for="upload"><b>Upload bestand </b><br />(Maximaal 2MB,<br />.gif, .jp(e)g, .png, .pdf)</label></td>
			<td class="contactUpload">Kies uw bestand: <input name="upload" type="file" /></td>
		</tr>
		<tr>
			<td class="contactLabelVraag"><label for="captcha"><b>Neem over </b>*<br />(Beveiligingsmaatregel)</label></td>
			<td></td>
		</tr>
		<tr>
			<td class="contactLabel"></td>
			<td><input type="submit" name="Submit" id="Submit" value="Versturen" /></td>
		</tr>
	</table>
</fieldset>
</form>

Try to change your validate_form() to the following to correctly validate the email:

function validate_form()
{
   valid = true;
   var email=document.forms["contact"]["email"].value;
   var atpos=email.indexOf("@");
   var dotpos=email.lastIndexOf(".");
   if ((atpos<1) || (dotpos<atpos+2) || (dotpos+2>=email.length) || email.length<7){
      alert("Vul een goed e-mailadres.");
      valid=false;
   }
   return valid;
}

pls let know if it works.

Try to change your validate_form() to the following to correctly validate the email:

function validate_form()
{
   valid = true;
   var email=document.forms["contact"]["email"].value;
   var atpos=email.indexOf("@");
   var dotpos=email.lastIndexOf(".");
   if ((atpos<1) || (dotpos<atpos+2) || (dotpos+2>=email.length) || email.length<7){
      alert("Vul een goed e-mailadres.");
      valid=false;
   }
   return valid;
}

pls let know if it works.

That works exactly as wanted, thanks!

Though, could you please explain why my method wasn't working?

By the way, the "email.length<7"-part wasn't put between ()'s so I did that myself MHENRU. :)

glad to help.
you didn't specify the "value" in your walk through the html's DOM.
Ex:
where one of your if-statement's arguments was:
(document.contact.email.length < 7)
it should have been:
(document.contact.email.value.length < 7)
same with the other arguments that didn't work.

you weren't far off the mark with the logic in your script, but as you see the script i pasted also checks for the correct position of the "@" and "."'s.