The form property is used to reference the form object that contains the FileUpload box.
<html>
<head>
<title>Using FileUpload form property</title>
</head>
<body>
<script language="JavaScript">
<!--
function checkFiles(){
if (document.secret.file1.value == ""){
alert("You did not enter anything for file 1");
}
if (document.secret.file2.value == ""){
alert("You did not enter anything for file 2");
}
else {
alert("The files are okay and will be uploaded");
}
}
-->
</script>
<form name="secret">
Please choose two files to upload.
<br><br>
File 1:<input type="file" name="file1">
<br><br>
File 2:<input type="file" name="file2">
<br><br>
<input type="button" value="Verify" onClick='checkFiles()'>
</form>
</body>
</html>