how can I validate this simple contact us form?

[co.ador]

<div id="tresuno"> 
<p>Contac us we want to assist you better.....</p>
<div id="tresdos">
<form action="step2.php" method="post">
Name<br/><input name="username" type="text" id="username" />
<br/> 
Email<br/><input name="email" type="text" id="email"/>
<br/>
Message<br/><textarea  name="message"  cols="60" rows="8" id="message"></textarea>
<br/>
<input type="submit" value="Send your message" /><br/>
</form>
</div>
</div>

[PravinS]

You can use javascript validation

[co.ador]

Does anyone has a starting point on where to star to validate this form?

 

where to go, what do do?

[Shocker88]

As pbs said above, best to do this validation in javascript (using a library such as jQuery may help).

 

The only thing you'd really want to check server-side (in the php) in a simple contact form such as that, is whether the required fields are filled in.

 

ie. if you wanted to make sure they entered a name in:

if ($_POST['username'] == '') {
    echo 'Please make sure you enter a username before submitting the form.';
}
else {
   // process results
}

 

You could get more specific on which values they can enter in what field but that would require regex which is far more complex if you are new to validation.

[co.ador]

The above script will check weather username is equal to empty then, echo enter and input in the username input, let say.

 

Is there another way of checking a different posibility? Let say if the type of form being validated is retrieving information from a database instead of sending information Then I would say there is a possibility of checking weather a input is NULL meaning it doesn't match any of the record in the database. so the testing would be weather the index username is NULL instead of empty right?