eXtplorer - PHP-based File Manager

Hi, I need to post selected file to my code. In Extplorer I select line with TXT file name and then I need to post it to another code to generate PDF file. Any ideas, how can I do it?

I try to make javascript like:

requestParams = getRequestParams();

Ext.urlEncode( requestParams );
  if (requestParams.item.length>0){
//    pFileName = dirTree.getSelectionModel().getSelectedNode().id.replace( /_RRR_/g, '/' ) + '/' + pRow[0].get('name');
//    pFileName = pRow[0].get('name');
    pFormToPDF = document.createElement('form');
    pFormToPDF.action = '<?php echo _EXT_URL . "/csvtopdf.php?lang=" . $GLOBALS["language"] ?>' + '&' + Ext.urlEncode( requestParams );
    pFormToPDF.method = 'post';
    pFormToPDF.enctype = 'multipart/form-data';

pFileInput= document.createElement('input');
    pFileInput.type = 'file';
    pFileInput.name = 'csvfile';
    pFileInput.value = dirTree.getSelectionModel().getSelectedNode().id.replace( /_RRR_/g, '/' ) + '/' + requestParams.item[0];

pFormToPDF.appendChild(pFileInput);

document.getElementById('convertForm').appendChild(pFormToPDF);

pFormToPDF.submit();
  }

but with SecurityError: The operation is insecure. at "pFileInput.value = dirTree.getSelectionModel().getSelectedNode().id.replace( /_RRR_/g, '/' ) + '/' + requestParams.item⁰;" line.

Thanks for any ideas.

Netrva