AJAX Suggest: The PHP File
Start typing a course in the input field:

Suggestions:
The page on the server called by the JavaScript is a PHP file called GetHint.php, which checks an array of course titles, and returns the corresponding title(s) to the browser. If there is any text sent from the JavaScript (strlen($q)>0), the following happens:
  1. Find a title matching the characters sent from the JavaScript.

  2. If no match were found, set the response string to “No suggestion.”

  3. If one or more matching titles were found, set the response string to all these titles.

  4. The response is sent to the txtHint placeholder. 
<?php
  // Fill up array with course titles.
  $a[] = "160 Computer Science I";
  $a[] = "161 Computer Science II";
  $a[] = "230 Systems Programming";
  $a[] = "242 Algorithms and Data Structures";
  $a[] = "289 Social Implications of Computer Technology";
  $a[] = "363 User Interface Design";
  $a[] = "365 Organization of Programming Languages";
  $a[] = "451 Operating Systems I";
  $a[] = "457 Electronic Commerce Systems";
  $a[] = "465 Principles of Translation";
  $a[] = "Chem121 General Chemistry I";
  $a[] = "Chem122 General Chemistry II";
  $a[] = "Comm110 Fundamentals of Public Speaking";
  $a[] = "EE201 Introduction to Digital Electronics";
  $a[] = "EE202 Electrical Engineering Laboratory";
  $a[] = "Engl110 College Composition I";
  $a[] = "Engl130 Composition II: Writing for Public Audiences";
  $a[] = "Math146 Applied Calculus I";
  $a[] = "Math165 Calculus I";
  $a[] = "Math166 Calculus II";
  $a[] = "Math208 Discrete Mathematics";
  $a[] = "Math321 Applied Statistical Methods";

  // Get the q parameter from URL.
  $q = $_GET["q"];

  // Look up all hints from array if length of q > 0.
  if ( strlen($q) > 0 ) {
    $hint = "";
    for ( $i=0; $i<count($a); $i++ )
      if ( strtolower($q) ==
           strtolower( substr( $a[$i], 0, strlen($q) ) ) )
        if ( $hint == "" )
          $hint = $a[$i];
        else
          $hint = $hint . ", " . $a[$i];
  }

  // Set output to "no suggestion" if no hint were found
  //   or to the correct values.
  if ( $hint == "" )
    $response = "No suggestion";
  else
    $response = $hint;

  // Output the response.
  echo $response;
?>