character limit

another beginners question from yours truly but i was just wondering how i would code a character limit on one of my fields iv been around the internet but i cant find what i need cause i usually come up with the same error code each time. if anyone knows what to do that would be great, hears the code iv been using.

<?php
$con = mysqli_connect("localhost","root","","nib");
// Check connection
if (mysqli_connect_errno())
{
	echo "Failed to connect to MySQL: " . mysqli_connect_error();
}

// define variables and set to empty values

$companyname = $firstname = $address1 = $address2 = $area = $city = $postcode = $email = $website = $clubphone = $homephone = $mobilephone = $typeofbusiness = $renewaldate = "";

if ($_SERVER["REQUEST_METHOD"] == "POST")
{
 $errors = array();
 if (empty($_POST["companyname"]))
{
    $errors['companyname'] = "Please Enter Your companyname";
}
<input type='text' name='keywords' size='60' value='companyname' maxlength='10' /> 
elseif(strpos($_POST['companyname'], '/') !== false)
{
    $errors['companyname'] = 'Cannot use /';
}
elseif(strpos($_POST['companyname'], 'The') !== false)
{
    $errors['companyname'] = 'Company Names cant start with The';
}
elseif(strpos($_POST['companyname'], 'the') !== false)
{
    $errors['companyname'] = 'Company Names cant start with the';
}
elseif(strpos($_POST['companyname'], 'THE') !== false)
{
    $errors['companyname'] = 'Company Names cant start with THE';
}
else
{
   $companyname = test_input($_POST["companyname"]);
}

and heres the error code ive been getting.

aswell as this if i remove this symbol i get one to do with the else if statement witch i kinda need.

again if anyone has a solution please get back to me soon as