var LastInput=0, EmptyInput=0;

function AddFile()
{
    var tmp, tmp2, files, new_input;
    if(this.name.indexOf("file_")==0) { inputid = this.name.replace("file_", ""); tmp = this; }
    else { inputid = 0; tmp = document.getElementsByName("file_0")[0]; }
    if(tmp && tmp.value=='' && inputid!=EmptyInput)
    {
        tmp2 = document.getElementsByName("file_"+EmptyInput)[0];
        files = document.getElementById("files");
        //alert(tmp2);
        if(files && tmp2) { files.replaceChild(tmp, tmp2); }
        if(LastInput!=EmptyInput)
       {
           tmp2 = document.getElementsByName("file_"+LastInput)[0];
           if(tmp2)
           {
                   tmp2.setAttribute("name", "file_"+EmptyInput);
                   if(LastInput==inputid) inputid = EmptyInput;
           }
        }
        EmptyInput = inputid;
        --LastInput;
    }
    else if(tmp && tmp.value!='' && inputid==EmptyInput)
    {
        ++LastInput;
        EmptyInput = LastInput;
        new_input = document.createElement("input");
       new_input.setAttribute("type", "file");
       new_input.setAttribute("name", "file_"+LastInput);
       new_input.className = "textbox";
       new_input.onchange = AddFile;
       new_input.style.width = "400";
       new_input.style.margin = "2px";
       new_input.style.display = "block";
       files = document.getElementById("files");
       if(files) files.appendChild(new_input);
    }
}

[HTML] pobierz, plaintext 
<form method="post" enctype="multipart/form-data" onsubmit="document.getElementById('uploading').style.display='';"> 
<input type="hidden" name="action" value="upload"> 
<input type="hidden" name="dir" value=""> 
<div id="files"> 
<input type="file" name="file_0" class="textbox" onchange="AddFile();" style="width:400;margin:2px;display:block;"> 
</div> 
<input type="submit" value="Załaduj" class="button"> <input type="button" value="Zamknij" class="button" onClick="window.close();"> 
</form>
[HTML] pobierz, plaintext