How can i replace ajax id with a variable?

PHP
1

Hi can i put the ajax div into a variable
or instead of using get element by id can i use get element by $film
the reason i want to do that is that have the 3 files the ajax function, the query file, and the display page
now the display page display the ajax function using the (document.getElementById(‘ajaxFilmLink’) so on the display page i have a div=ajaxFilmLink. this returns the value fine but my problem now is that instead of a div=ajaxFilmLink i want a variable that works just like the div=ajaxFilmLink
because i need to store those values on jwplayer which usualy would be like this

 'file': '<?php echo $efilm; ?>',

i tried

 'file': '<?php echo div=ajaxFilmLink ; ?>',

but that doesnt work is there a way i can grab that ajax div value and store on a variable $efilm so that i can echo anywhere i want?
my files 3 files are the follwings
ajax file

var ajaxRequest10;
		// The variable that makes Ajax possible!		
	try
	{// Opera 8.0+, Firefox, Safari		
	   ajaxRequest10 = new XMLHttpRequest();
	}
	   catch (e)
	{// Internet Explorer Browsers		
		try
	{
		ajaxRequest10 = new ActiveXObject("Msxml2.XMLHTTP");
	}
	   catch (e)
	{
		try
	{
		ajaxRequest10 = new ActiveXObject("Microsoft.XMLHTTP");
	} 
	   catch (e)
	{// Something went wrong				
	   alert("Your browser broke!");
	return false;
  }	
 }
}	
		// ********** DATA 10 ********** FILM LINK	
		// Create a function that will receive data sent from the server	
ajaxRequest10.onreadystatechange = function()
	{
		if(ajaxRequest10.readyState == 4)
		 {	
		 	var ajaxDisplay10 = document.getElementById('ajaxFilmLink');
			ajaxDisplay10.innerHTML = ajaxRequest10.responseText;
		}
	}	
		// var fid = document.getElementById('fid').value;	
var queryString10 = "?fid=" + fid;	ajaxRequest10.open("GET", "../jrp/setfilmlink.php" + queryString10, true);	ajaxRequest10.send(null);

queryfile named (setfilmlink.php)

<?php
include("../../includes/config.php");
mysql_connect($db_address, $db_username, $db_password);mysql_select_db($db_name) or die(mysql_error());
$fid = $_GET['fid'];	
$fid = mysql_real_escape_string($fid);
$query10 = "SELECT * FROM films WHERE (film_id = '$fid')";	
$qry_result10 = mysql_query($query10) or die(mysql_error());
while($row10 = mysql_fetch_array($qry_result10))	
{	$urlfid="http://www.onfilm.biz/streaming/home/".$row10['client']."/".$row10['client_office']."/".$row10['filename'].".mp4";?>		
<a class="hofwhite14" href="#" onclick="loadNplay('<?php echo $urlfid; ?>')"><u></u>Property Film</u></a>
<?php	}mysql_close();
 //EDIT 290510
?>

and the display page is named (indextest.php)

<div id="ajaxFilmLink">
 </div>

the main reason i want to change is because when i simple try to put the query page on the indextest.php page the query doesnt retrieve the data from the database
so can i put the ajax div into a variable
or instead of using get element by id can i use get element by $film