validation and default value

Greetings

I have a form with a text field for name,
I don't want to have a label for the field (so that in CSS I use a display none)
in the advanced section of the field editor I use the 'default value' that prepoluate the field with the value 'name'

my problem now is that if the user press the submit menu without changing 'name' to his name, the field will still validate

how can I do to avoid that behaviour while still using the default value, is there a blacklist word or something similar that would make the field not validate?

I face the very same problem with a select menu where I have used

[php
 //Creating drop down item array.
    $items = array();

    //Adding initial blank value.
    $items[] = array("text" => "Select the destination", "value" => "");
	$items[] = array("text" => "----------------------", "value" => "");

if people don't select a value, then it is a blank value, but still it validates

Thank you in advance for your assistance

Greetings Chris

Thank you for your answer

I have been to the link, and I already followed the advise to enable value blanck for the first option.
that is actually what I did on the code I sent here.
but it seems that it auto feed the option value

//Adding initial blank value.
    $items[] = array("text" => "Select the destination", "value" => "");
	$items[] = array("text" => "----------------------", "value" => "");

I thought that would have print me

<option value='' >Select the destination</option>
<option value='' >----------------------</option>

and THAT would have fired me an error, I guess

BUT
actualy it prints me the following

<option value='Select the destination' >Select the destination</option>
<option value='----------------------' >----------------------</option>

which validate

any idea why my snipet does not work? why the option value is auto poluated with the "text" value

thank you in advance for your help