Hello guys, I am working with javascript and currently have the below code set up.

This works well, however I would like to change the "select box" to a "search box"-

When the user enters a search string, the matching DIV appears. If there is no matching DIV then "sorry nothing found" appears.

Is this possible at all?

Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta http-equiv="Content-Style-Type" content="text/css">
<meta http-equiv="Content-Script-Type" content="text/javascript">
</head>
<body>
<script type="text/javascript">
function show(obj) {
no = obj.options[obj.selectedIndex].value;
count = obj.options.length;
for(i=1;i<=count;i++)
document.getElementById('fleet'+i).style.display = 'none';
if(no>0)
document.getElementById('fleet'+no).style.display = 'block';
}
</script>


<form name="myForm">
<select onchange="show(this)">
<option value="1">Please Choose</option>
<option value="2">120</option>
<option value="3">121</option>
<option value="4">122</option>

</select>
</form>



<div id="fleet1" style="display:block">Please Choose	<br>
</div>



<div id="fleet2" style="display:none">	<br>
<table valign="top" align="center" border="0" width="690" style="border-collapse: collapse" cellpadding="0" cellspacing="0" 

bgcolor="#336699">
	<TR border="0" bordercolor="#FFFFFF">
	<TD valign="top">
         <?php include("php/fleet/includes/table.php"); ?>
<?php
   $path = $_SERVER['DOCUMENT_ROOT'];
   $path .= "/php/fleet/120.php";
   include_once($path);
?></tr></table>
</td>
</tr>
</table></div>



<div id="fleet3" style="display:none">	<br>
<table valign="top" align="center" border="0" width="690" style="border-collapse: collapse" cellpadding="0" cellspacing="0" 

bgcolor="#336699">
	<TR border="0" bordercolor="#FFFFFF">
	<TD valign="top">
         <?php include("php/fleet/includes/table.php"); ?>
<?php
   $path = $_SERVER['DOCUMENT_ROOT'];
   $path .= "/php/fleet/121.php";
   include_once($path);
?></tr></table>
</td>
</tr>
</table></div>

<div id="fleet4" style="display:none">	<br>
<table valign="top" align="center" border="0" width="690" style="border-collapse: collapse" cellpadding="0" cellspacing="0" 

bgcolor="#336699">
	<TR border="0" bordercolor="#FFFFFF">
	<TD valign="top">
         <?php include("php/fleet/includes/table.php"); ?>
<?php
   $path = $_SERVER['DOCUMENT_ROOT'];
   $path .= "/php/fleet/122.php";
   include_once($path);
?></tr></table>
</td>
</tr>
</table></div>
</body>
</html>
demo can be seen here:
http://www.nctfleetlist.co.uk/div.php