Fields must not be null

[MitchEvans]

If one of the fields is not filled in I want a message to come up and say "all fields must be filled in" when the button is clicked and a field is NULL.

Any idea what code i would put in here for that to happen?

<form method='post' action='email1.php?host=$host1&script=$script1'>
Enter Your e-mail address:<input type='text' name='mytext1'>
Enter Your Friends e-mail address:<input type='text' name='mytext'>
<INPUT type='submit' name='mybutton' value='Click me!'>";

I'm thinking:

if 'mytext1' or 'mytext' =NULL then message(fill in all)

Not too sure where this would go and obviously the code above is just a guideline

[rincewind456]

$mytext = trim($_POST['mytext']);

if ($mytext == "" ){
		print "your error message here";
	}

[MitchEvans]

Yeah thats great makes sense cheers, any idea where this would be put in my code so that when the button is clicked the error message appears?

[rincewind456]

Well you would do it with the rest of your form processing and then return the page to be filled in properly if there was a problem.

Or you could do it with javascript before it is submitted like this

<script type="text/javascript">
function checkForm(form) {
for (var i = 0; i < form.elements.length; i++) {
if (form.elements[i].value == "") {
alert("Fill out ALL fields.");
return false;
}
}
return true;
}
</script>
<form onsubmit="return checkForm(this)" method='post' action='email1.php?host=$host1&script=$script1'>
Enter Your e-mail address:<input type='text' name='mytext1' >
Enter Your Friends e-mail address:<input type='text' name='mytext'>
<INPUT type='submit' name='mybutton' value='Click me!' >";
<br />
</form>

[MitchEvans]

That works fantastically thank you so much!
You're extermely knowledged in php, I hope soon I too can help us newbies in the field of php!