Scripting the Applet Using Client-Side JavaScript

The previous lessons demonstrated manipulating JFile's upload and download applets using HTML <param> tags. You can also control JFile in JavaScript. JFile's numerous JavaScript methods are defined in the UploadClient Applet and DownloadClient Applet sections of the Programmer's Reference. The following exercise hides JFile's ready-made file list and transfer status windows. This allows you to create your own user interface. We will create a very simple interface: an upload button. When clicked, the button will call JFile's startUpload method. JavaScript methods are case-sensitive.

Using JFile's startUpload method

Exercise 3: Scripting the Applet Using Client-Side JavaScript

1. If you created the physical and virtual JFileScripts directories in A Simple Upload or A Simple Download, go to Step 4. If you did not create the directories, go to Step 2.
   
   
2. Create a directory called JFileScripts.
   
   
3. Create a virtual directory called JFileScripts and map it to the physical JFileScripts you created in Step 2:
   
   
   1. Open the Internet Information Services (IIS) explorer.
   2. Right-click Default Web Site.
   3. Select New -> Virtual Directory.
   4. For Alias, enter JFileScripts.
   5. Browse to the JFileScripts directory you created in step 1.
   6. Check "Read" and "Run scripts."
   7. Click "Finish."
   
   
4. Copy filetransfer.jar (for Netscape) and/or filetransfer.cab (for Internet Explorer) to the directory JFileScripts. These files are in JFile's installation directory (by default, C:\Program Files\SoftArtisans\JFile).
   
   
5. Copy formresp.asp to the directory JFileScripts. Formresp.asp is a server-side upload processing script that you will find in JFile's Samples\Upload\Simple directory (installed by default at C:\Program Files\SoftArtisans\JFile). Formresp.asp uses SoftArtisans FileUp to process the upload.
   
   
6. Create an HTML script containing the following lines. Name the script scriptapplet.htm and save it in your JFileScripts directory.

   <APPLET codebase="/JFileScripts" code="softartisans.filetransfer.UploadClient.class" 
   height="0" width="0" mayscript archive="filetransfer.jar" name="fileupload">
   
   	<!-- The Cabbase parameter specifies the cab file containing the applet. -->
   	<PARAM name="cabbase" value="filetransfer.cab">	
   	
   	<!-- The PostURL parameter specifies the URL to which the file will be posted. -->	
   	<PARAM name="PostURL" value="http://localhost/jfilescripts/formresp.asp">
   	
   	<!-- The FileName# parameter specifies a file to transfer.  When uploading more than one file, use 
   	"FileName1," "FileName2," etc. -->
   	<PARAM name="Filename1" value="c:\boot.ini">
   	
   	<!-- The HideFileList and HideTransferStatus parameters hide JFile's file list and transfer status windows, 
   	allowing the programmer to control the user interface. -->
   	<PARAM name="HideFileList" value="1">
   	<PARAM name="HideTransferStatus" value="1">
   </APPLET>
   
   <!-- Create a button that calls JFile's startUpload method. -->
   <input type="button" value="Upload c:\boot.ini" onclick="document.fileupload.startUpload();">
   

   Understanding the Script

   • The APPLET tag adds JFile's UploadClient applet to your web page. We assigned values to several APPLET attributes:
     
     
     • Codebase
       Specifies the directory containing the UploadClient's Java class. If the Java class is in the same directory as the script referencing it - as it is in this exercise - Codebase is optional. When the Java class is in a different directory, specify the complete relative path or URL.
       
       
     • Code
       Specifies the name of the applet's Java class. UploadClient is JFile's upload applet. Java class names are case-sensitive.
       
       
     • Height and Width
       Specify the height and width, in pixels, of a browser-embedded applet. By default, the applet is displayed in a pop-up window. To embed the applet in the main browser window, set the parameter UseAppletInBrowser to 1, as follows.

       	<PARAM name="UseAppletInBrowser" value=1>

       If you do not set UseAppletInBrowser to 1, that is, if you display the applet in a separate window, set Height and Width to 0.
       
       
     • Mayscript
       Specifies that the applet can be manipulated in script.
       
       
     • Archive
       Specifies the archive file containing the Java applet. Filetransfer.jar contains JFile's Java class files for Netscape Navigator.
       
       
     • Name
       Specifies a variable name for this instance of the UploadClient applet. You can assign any name to Name. Use the name you assign to reference the UploadClient applet in script.
       
       
   • The Cabbase parameter specifies the cab file containing the Java applet. Filetransfer.cab contains JFile's Java class files for Internet Explorer.
     
     
   • The PostURL parameter specifies the URL to which the file will be posted, http://localhost/jfilescripts/formresp.asp. Formresp.asp uses SoftArtisans FileUp to process the upload.
     
     
   • The FileNameN parameter specifies a file to transfer. When uploading more than one file, use "FileName1," "FileName2," etc.
     
     
   • When set to 1, the HideFileList parameter hides JFile's ready-made file-list window (displayed in A Simple Upload). Hiding the file-list window allows you to control the user interface in script.
     
     
   • When set to 1, the HideTransferStatus parameter hides JFile's ready-made transfer status window.
     
     
   • When clicked, the "Upload c:\boot.ini" button calls the UploadClient's startUpload method, which initiates the file transfer.
     
     

     JavaScript methods are case-sensitive.

   
   
   
   

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