The different buttons/methods are:

Button Name	Function/Implementation	Description
btnAdd	btnAddClick()	Invokes the "AddFiles" function. A "file-open dialog" is displayed and a user can select multiple files from a single folder.
btnAddFolder	btnAddFolderClick()	Invokes the "addFolder" function. A "Select Folder" dialog is displayed and the user can choose a folder for which all files and optionally files in sub-folders will be added to the list of files for uploading.
btnRemove	btnRemoveClick()	Removes selected files from the list of files for uploading.
btnSelectAll	btnSelectAllClick()	Selects all files in the files view.
btnOpen	btnOpenClick()	Opens a previously saved list of upload files.
btnSave	btnSaveClick()	Saves the current list of files so that the files can be re-uploaded at another time when they have been edited or changed.
btnUpload	btnUploadClick()	Causes the control to upload all files currently loaded in the files list.

Example of calling the method for button "btnAddFolder" , assuming you have a JScript variable called xBoomerang and you are using a custom toolbar.

<script language='javaScript' type='text/javaScript'>
  xBoomerang.btnAddFolderClick();// Shows "Add folder" dialog.
</script>

<input type="button" onClick="javaScript: xBoomerang.btnAddFolderClick();" >

  if (myform.SURNAME.value = "") {
    alert("Please enter your surname");
    myActiveX.cancelSubmit();
    return false;
  }

  function myXControl_OnXReady() {
    myXControl.URLTo = "myUploadScript.asp";
    myXControl.RedirectTo = "RedirectScript.asp";
    myXControl.URLLicense = "axlicense.dat";  
  }

  myXControl.attachEvent("OnXReady",myXControl_OnXReady);

Define the object
<OBJECT
   id='Boomerang1'
   name='Boomerang1'
   classid='clsid:880A66FC-DFCB-4950-87DC-0B49BA501517'
   codebase = 'http://www.activexobjects.com/codewarehouse/activex/1890/BoomerangUpload.cab#version=2,0,0,0'
   width    = '100%'
   height   = '100%'
   align    = 'center'
   vAlign   = 'center'
   hspace   = '2'
   vspace   = '2'
   StandBy  = 'Please wait for Boomerang Upload control to download. Once installed it will load quickly.'
 >
  Handle non-activex browsers by putting in a form where
  files can be uploaded one at a time.
   <!--
     ALTERNATIVE CONTROLS FOR NON-ACTIVEX BROWSERS
       If a browser cannot load the activex control, it will load whatever html code
       is here in inner part of the object tags. If it can load the object, it will ignore
       the code in the inner part of the object tags.
   -->
   <form name="frmUpload" id="frmUpload"
         action="/demox/fileupload.asp"
         method="POST"
         enctype="multipart/form-data"
      >
      <table class="tcontent" style="border-style: solid;border-width:1px;border-color:black" width="100%">
        <tr>
          <td>
            <input type="file" name="file1">
          </td>
        </tr>
        <tr>
          <td>
            <input type="file" name="file2">
          </td>
        </tr>
        <tr>
          <td>
            <input type="submit" name="btnSubmit" value="Upload File/s" class="button">
          </td>
        </tr>
      </table>
    </form>

 </OBJECT>
Use javaScript to setup the Boomerang control
 <script language='javaScript' type='text/javaScript'>
   // Preferably initialise properties for control
   // when it has indicated that it is fully loaded and ready .
   var xUA = navigator.userAgent.toLowerCase();
   var isIE = xUA.indexOf('msie')!=-1;
   if (isIE && document.all)// Only script here for ie
   {
     var xBoomerang = document.all.Boomerang1;// read object out of document
     function Boomerang1_OnXReady() { // event handler function. Boomerang is ready
       if (xBoomerang) { // safety !!!
         // set properties
         // Max number of files allowed to upload
         xBoomerang.MaxFileCount          = "16";
         // +/- 0.5 MB Max File Size Allowed
         xBoomerang.MaxFileSize           = "500000";
         // +/- 2MB Total size of files accepted
         xBoomerang.MaxTotalSize          = "2000000";
         xBoomerang.UploadControlsEnabled = true;// Allow user to upload from upload button
         // Post using internal control HTTP functions
         xBoomerang.PostWithBrowser       = false;
         xBoomerang.Filter                = "All Files(*.*)|*.*";// 2MB
         // Where the control uploads files to ...
         xBoomerang.URLTo                 = "upload/fileupload.asp";
         // Alternative. Blank here but could be FTP
         xBoomerang.URLToAlt              = "";
         // After upload, control will send results here
         xBoomerang.RedirectTo            = "upload/fileuploadreply.asp";
       }
     }
     // Attach object events . This is important! The control must initialize.
     if (xBoomerang) {
       // When control initializes it will call the Boomerang1_OnXReady function
       xBoomerang.attachEvent("OnXReady",Boomerang1_OnXReady);

     }
   }
 </script>
 <noscript>
This would get called if the browser did not support javaScript.
 <!--
 Inform users of need to enable javaScript if you think it necessary for
  your web page . The noscript tag is generally shown when scripting is disabled,
  but not when a scripting language is unsupported. Hence, always use javaScript.
 -->
   This page requires that you enable client scripting.
 </noscript>