1) Change the program so that instead of using "childNodes" 
it uses "nextSibling" for looping through the nodes.


$node = $doc->documentElement->firstChild;
while ($node) {
    if ($node->nodeType == 1) {
       echo $node->tagName. " : ";
       $innerNode = $node->firstChild;                  
       while ($innerNode) {  
          if ($innerNode->nodeType == 1) {  
             echo $innerNode->tagName ." = ". $innerNode->nodeValue ."; ";  
          }  
          $innerNode = $innerNode->nextSibling;  
       }  
       echo "<br/>";
    }
    $node = $node->nextSibling;   
}


-----------------------------------------

2) Print all the titles of the movies by looping through the nodes 
which have "title" as their tag name and printing their "textContent".

$titles = $doc->getElementsByTagName("title");
foreach($titles as $node) {
   print $node->textContent . " ";
}

OR:

$titles = $doc->getElementsByTagName("title");
for ($i = 0; $i < $titles->length; $i++) {
   print $titles->item($i)->textContent . " ";
} 



-----------------------------------------

3) Find the movie from the year "1998" and print the 
textContent of its parentNode.

$year = $doc->getElementsByTagName("year");  
foreach($year as $node) {  
   if ($node->textContent == "1998") {
      print $node->parentNode->textContent . " ";                         
   }
}

-----------------------------------------

4) Read the contents of the XML file into a data structure that 
contains the movies and their titles, actor and years.

$topElem = $doc->documentElement;
$movies = array();
foreach ($topElem->childNodes AS $item) {
  if ($item->nodeType == 1) {
     $temp = array();
     foreach ($item->childNodes AS $bottomItem) {
        if ($bottomItem->nodeType == 1) {
            $temp[$bottomItem->tagName] = $bottomItem->nodeValue;
        }
     }
     array_push($movies,$temp);
  }
}    
echo "<pre>";
print_r($movies);
echo "</pre>";


-----------------------------------------

6) Change the code so that tag names are printed in italics and the 
ID attributes are printed in bold face.

In the startElement function change the echo statement to:

echo "<i>$name</i>: <b>{$attrs["ID"]}</b>";

-----------------------------------------

7) Print only the titles of the movies.

In the startElement function:

    global $istitle;
    ...
    if ($name == "TITLE") {
    echo "$name: ";
        $istitle = true;
    } else {
        $istitle = false;  
    }

In the handler function:

    global $istitle;
    if ($istitle == true) {
      echo "$data";
    }

-----------------------------------------

8) Print only the movie titles.

<?php
$filecontent = implode('', file('movies.xml'));
$p = xml_parser_create();
xml_parse_into_struct($p, $filecontent, $vals, $index);
xml_parser_free($p);
foreach ($vals AS $item) {
    if ($item['tag'] == 'TITLE') {
        echo $item['value']."<br>";      
    }
}
?>