อยากทราบวิธีการเช็คว่าในไฟล์ฟิล มีข้อมูลเลือกแล้วหรือไม่ครับ

    <script language="javascript">
//check Input

function fncSubmit()

{
if(document.form1.txtUsername.value.length<13 )
{

alert('กรุณาตรวจสอบเลข ISBN อีกครั้ง');
document.form1.txtUsername.focus();




//
return false;
}  
if(document.form1.book_press.value == "0")
{

alert('Please input Input 9');
//document.form1.book_press.focus();       
//

//
return false;
}  
if(document.form2.fileUpload.value == "")
{

alert('Please input Input 10');
//document.form1.book_press.focus();       
//



return false;
}  
document.form1.submit();
}


//end check input
</script>

<?
//upload image 2
	for($i=0;$i<count($_FILES["fileUpload2"]["name"]);$i++)
	{
		if(trim($_FILES["fileUpload2"]["tmp_name"][$i]) != "")
		{
			$images = $_FILES["fileUpload2"]["tmp_name"][$i];
			$new_images = $_FILES["fileUpload2"]["name"][$i];
			
			copy($_FILES["fileUpload2"]["tmp_name"][$i],"MyResize/$txtUsername"."_2_".$_FILES["fileUpload2"]["name"][$i]);
			
			$width=640; //*** Fix Width & Heigh (Autu caculate) ***//
			$size=GetimageSize($images);
			$height=round($width*$size[1]/$size[0]);
			$images_orig = ImageCreateFromJPEG($images);
			$photoX = ImagesX($images_orig);
			$photoY = ImagesY($images_orig);
			$images_fin = ImageCreateTrueColor($width, $height);
			ImageCopyResampled($images_fin, $images_orig, 0, 0, 0, 0, $width+1, $height+1, $photoX, $photoY);
			ImageJPEG($images_fin,"MyResize/$txtUsername".$new_images);
			ImageDestroy($images_orig);
			ImageDestroy($images_fin);
			
			
			
			//User Make No Echo
			//echo "Resize Successful.<br>";

			//*** Insert Record ***//
			$objConnect = mysql_connect("localhost","library","compaq") or die("Error Connect to Database");
			$objDB = mysql_select_db("library");
			$strSQL = "INSERT INTO book_image";
			$strSQL .="(image_path,book_isbn,image_type) VALUES 
			('"."MyResize/".$_POST['txtUsername']."_2_".$_FILES["fileUpload2"]["name"][$i]."','".$_POST['txtUsername']."','2')";
			
			$objQuery = mysql_query($strSQL) or die(mysql_error());
		
		}
		
		
	}
//end upload image 2
?>