PHP Level Two Linkage menu

<?php
PHP section:
Get the pull down linkage data
Require ("conn.php");
$result =mysql_query ("SELECT * from units left JOIN the users on (Users.unit=units.unid)");
$mx =mysql_num_rows ($result);

for ($i =0; $i < $mx; $i + +) {
$r =mysql_fetch_array ($result);
$uname = $r [' uname '];
$unid = $r [' Unid '];
$usname = $r [' username '];
$usid = $r [' userid '];

if ($lasun!= $uname) {
$java 1= $java 1. "$uname", ";
$java 2= $java 2. "$unid", ";
$lasun = $uname;
if ($i >0) {
$java 3= $java 3. "],[";
$java 4= $java 4. "],[";
}
} else {
$java 3= $java 3. ",";
$java 4= $java 4. ",";
}

$java 3= $java 3. "" $usname "";
$java 4= $java 4. "" $usid "";

}

$java 1 = "[".   Substr_replace ($java 1, "",-1). "]n";
$java 2 = "[".   Substr_replace ($java 2, "",-1).   "]n";
$java 3 = "[[].   $java 3. "]]n";
$java 4 = "[[].   $java 4. "]]n";



JavaScript section
?>
<script language= "JavaScript" defer>
var fmenu = <?= $java 1?>
var fvalue = <?= $java 2?>
var smenu = <?= $java 3?>
var svalue = <?= $java 4?>

var owhere = Document.all.tar;
var ofmenu = document.createelement ("<select name= ' Unid ' >");
var osmenu = document.createelement ("<select name= ' Usid ' >");
With (Owhere) appendchild (Ofmenu), appendchild (Osmenu);

Createmainoptions ();
Createsuboptions (0);

Ofmenu.onchange = function () {createsuboptions (this.selectedindex);};

function Createmainoptions () {
for (Var i=0;i<fmenu.length;i++) ofmenu.options[i] = new Option (fmenu[i],fvalue[i));
}
function Createsuboptions (j) {
With (Osmenu) {
length=0;
for (Var i=0;i<smenu[j].length;i++) osmenu.options[i] = new Option (smenu[j][i],svalue[j][i));
}
}

function checkuser () {
if (document.forms[1].elements[1].value== "") {alert ("No user selected");   return false; }
}
</SCRIPT>

<!--referencing--> in HTML
<div id= "tar" style= "Display:inline" ></div>
<!--
Additional data table structure with users and units
Table Users:
Userid
Username
Unit

Table units:
Unid
Uname