Use of substr()

Hello all; I am scratching my head over the following: I have written code that is supposed to format text sent from a form in a textarea form element. This text does not have new lines added if the text is allowed to automatically wrap to the next line. I want to automatically add new lines to this input at appropriate locations. Here is the code I wrote: (It is in early stages of development) function format_text($a, $b) // $a is text to format, from textarea, $b is line length

                    { $line = array();
                       $limit = (strlen($a)/$b);
                      for($i = 0; $i < $limit; $i++)
                         {
                            $start = $i*$b;
                            $stop = (($i*$b) + $b) - 1;
                            print "start : $start     stop : $stop<br>";
                            array_push($line, substr($a, $start, $stop)); // separate into lines not greater than $b length
                         }
                    return $line;
                     }

Here is what is entered in a test run: (actual text has no new lines, I added them here) Then let us test a long string that spans more than the line length of the text area field. This is the way I practice both writing and typing. If I could only get by the booby traps and land mines with my typing, I could get somewhere. This is output code: if($_POST['input']) {print strlen($_POST['input']); print'<br>'; $output = array(); $output = format_text($_POST['input'], 60); for($i = 0; $i < count($output); $i++)

      { print "$i :".$output[$i].'<br>'; }

} Here is what comes out the other end: 239 start : 0 stop : 59 start : 60 stop : 119 start : 120 stop : 179 start : 180 stop : 239 0 :Then let us test a long string that spans more than the lin 1 : length of the text area field. This is the way I practice both writing and typing. If I could only get by the booby tr 2 :oth writing and typing. If I could only get by the booby traps and land mines with my typing, I could get somewhere. 3 :ps and land mines with my typing, I could get somewhere. // e is missing from end of line 0 // portions of the text are repeated out of sequence. The questions I have are: What does the browser actually do when it automatically wraps textarea input? What could explain the scrambled result? Thanks much to anyone taking the time: Jeff K