PHP: Function eregi() is deprecated

eregi() is deprecated as of PHP 5.3, use preg_match() instead.

Note that preg_match() is only case insensitive when you pass the i modifier in your regular expression. Example:

include 'db_connect.php'; 
if(isset($_POST['Submit']))           
{            
    $acc_type=ucwords($_POST['acc_type']);
    $minbalance=ucwords($_POST['minbalance']);

    // Removed A-Z here, since the regular expression is case-insensitive                
    if (!preg_match("/^[a-z ]+$/i", stripslashes(trim($acc_type))))//line 20 
    {                 
        echo "Enter Valid Data for Account Type!";                
        exit(0);                 
    }           
    else 
    {                  
        // \d and 0-9 do the same thing
        if (!preg_match("/^[\d ]+$/", stripslashes(trim($minbalance))))//line 27
        {
        }
    }
}