Ok, thanks.

I check the total file size inside the handler of the javascript "select" event of the UploadAttachments object.

It has not been that straight forward because inside the "select" event handler, the parameter "files" contains only the files selected in the last "Browse" dialog opened, and it does not contain files eventually selected previously (supposing the user click more times on the "Browse" button to select files in different folder, and eventually remove files from the list of files selected). Anyway, I managed to make it work as I want.

 

One question:

 

The Javascript API documentation (http://ajaxuploader.com/document/scr/JavaScript-API.htm) only features the events that can be handled. Is there somewhere a documentation of the UploaderAttachements properties and method available on client script? I mean, after this line:

var hidden=document.getElementById('<%=Uploader1.ClientID%>')

what can I do with my object hidden?