I've developed a WYSIWYG flash backend for a client's flash site, and what you're doing is possible certainly : )
Is this a file upload? If so, you're going to be restricted to internet explorer only. Mozilla/Netscape, and presumably other browsers (not tested) consider using the javascript element click() method to trigger an upload "Browse" button a security problem. Here's the script from that site:
index.html:
<html>
<head>
<title>MyClient Admin</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<frameset cols="100%,0" frameborder="NO" border="0" framespacing="0">
<frame name="main" scrolling="AUTO" noresize src="flash.php">
<frame name="controller" scrolling="NO" noresize src="upload.php">
</frameset>
<noframes><body bgcolor="#FFFFFF" text="#000000">
</body></noframes>
</html>
upload.php:
<?php
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Pragma: no-cache");
if(isset($_POST['fileup'])==true) {
require("hft_uploader.php");
require("hft_image.php");
require("class.cropcanvas.php");
$filenames=array();
foreach($HTTP_POST_FILES as $key=>$value)
{
if($HTTP_POST_FILES[$key]['tmp_name']!="")
{
$uploader = new hft_uploader($key, "../images", "image/jpeg image/pjpeg", 1000000, 108);
$filename = time().rand(1,10).$uploader->original_name;
$filenames[] = array($key, $filename);
if($uploader->store_upload($filename))
{
$original_image = "../images/".$filename;
switch($key)
{
case ("itemFullUF"):
case ("diningItemFullUF"):
$width = 320;
$height = 240;
break;
case ("catTnUF"):
case ("diningItemTnUF"):
$width = 80;
$height = 60;
break;
default:
$width = 64;
$height = 48;
}
$image = new hft_image($original_image);
$image->resize($width, $height, '+');
$image->output_resized($original_image, "JPEG");
$cc = new canvasCrop();
$cc->loadImage($original_image);
$cc->cropToSize($width,$height,ccCENTRE);
$cc->saveImage($original_image);
chmod("../images/".$filename, 0644);
}
}
}
}
?>
<html>
<head>
<title>Upload</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<SCRIPT LANGUAGE=JavaScript>
<!--
function upit(fld)
{
var upObj = eval("document.forms.upload."+fld);
upObj.click()
while(upObj.value == "")
{
setTimeout(100)
}
upControl(fld)
}
function submitIt(){
document.upload.submit()
}
function upControl()
{
var obj=parent.main.admin;
var re = new RegExp("\\\\", "g");
for (var i=0; i<document.upload.elements.length; i++)
{
if(document.upload.elements[i].type=="file" && document.upload.elements[i].value!="")
{
var fileval = document.upload.elements[i].value;
var retSt = fileval.replace(re, "/");
if (obj) eval('obj.SetVariable("_root."+document.upload.elements[i].name, "' + retSt + '")');
}
}
}
<?php
if(count($filenames)>0) {
?>
var obj=parent.main.admin;
<?
foreach($filenames as $key=>$value)
{
?>
if (obj) eval('obj.SetVariable("_root.<?php echo $filenames[$key][0]; ?>", "<?php echo $filenames[$key][1]; ?>")');
<?php
}
?>
if (obj) eval('obj.SetVariable("_root.UF", "<?php echo $filenames[0][0]; ?>")');
window.location="bounce.php";
<?php
}
?>
//-->
</SCRIPT>
</head>
<body bgcolor="#000000" text="#FFFFFF">
<form name="upload" enctype="multipart/form-data" method="post" action="uploader.php">
<input type="file" name="catTnUF">
<input type="file" name="itemTnUF">
<input type="file" name="itemFullUF">
<input type="file" name="diningItemTnUF">
<input type="file" name="diningItemFullUF">
<input type="hidden" name="fileup" value="yes">
<input type="submit" value="Submit it">
</form>
</body>
</html>
bounce.php
<?php
header("Location: http://www.hostfs.net/lubahati.com/admin/uploader.php");
exit;
?>
flash.php:
<html>
<head>
<SCRIPT LANGUAGE=JavaScript>
<!--
function upit(fld)
{
var upObj = eval("parent.controller.document.forms.upload."+fld);
upObj.click()
while(upObj.value == "")
{
setTimeout(100)
}
parent.controller.upControl()
}
function submitIt(){
parent.controller.document.upload.submit()
}
//-->
</SCRIPT>
<title></title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<body bgcolor="#0d155e">
<object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="http://fpdownload.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,0,0" width="800" height="650" id="admin" align="middle">
<param name="allowScriptAccess" value="sameDomain" />
<param name="movie" value="admin.swf?<?php echo time(); ?>" />
<param name="quality" value="high" />
<param name="bgcolor" value="#0d155e" />
<embed src="admin.swf?<?php echo time(); ?>" quality="high" bgcolor="#0d155e" width="800" height="650" name="admin" align="middle" swliveconnect=true allowScriptAccess="sameDomain" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer" />
</embed>
</object>
</body>
</html>
Now obviously this is a little more complicated than it should be, but that's because it's meant to handle a variety of different fields smartly from flash. Also the bounce is not necessary, but I use it to make sure if the client uses the 'refresh' button on their browser or hits F5 it doesn't:
A) nag them with the 're-post form data' confirmation
B) re-post the form data!
If you have any problems slimming that code down, or have problems with the flash side, let me know : ) I may be a while, I just got busy and I'm going to be away for the weekend, but that's the general idea!