this post will help you to upload a file to the server with a new name
HTML
<form>
<input type="file" id="filelogo" class="fileUpload" accept="image/x-png,image/jpeg" /><br /><br />
<input type="button" value="Upload" onclick="UploadImage('filelogo','new name')" >
</form>
Java Script
function UploadImage(fnm,newname)
{
var data = new FormData();
data.append("filename", $("#"+fnm)[0].fil