Thankyou so much for your reply..Here is the way I calling the applet..When I drag and drop a file extention which is not allowed by the applet, the error still displays in the progress bar rather than as a javascript error
document.writeln(' classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93" WIDTH="590" HEIGHT="300" NAME="fileupload" codebase="
http://java.sun.com/update/1.4.2/jinsta ... on=1,4,0,0">');
document.writeln('<PARAM NAME=CODE VALUE="jfileupload.upload.client.MApplet.class">');
document.writeln('<PARAM NAME=CODEBASE VALUE="./">');
document.writeln('<PARAM NAME=ARCHIVE VALUE="lib/jfileupload.jar,lib/httpimpl.jar,lib/chttpclient.jar,lib/clogging.jar,lib/batchui.jar">');
document.writeln('<PARAM NAME=NAME VALUE="fileupload">');
document.writeln('<PARAM NAME="type" VALUE="application/x-java-applet;version=1.4">');
document.writeln('<PARAM NAME="scriptable" VALUE="true">');
document.writeln('<PARAM NAME="url" VALUE="' + PropUrl2 + '">');
document.writeln('<PARAM NAME="paramfile" VALUE="uploadfile">');
document.writeln('<PARAM NAME="param1" VALUE="todo">');
document.writeln('<PARAM NAME="value1" VALUE="upload">');
//document.writeln('<PARAM NAME="param2" VALUE="errorheader">');
//document.writeln('<PARAM NAME="value2" VALUE="custommessage">');
//document.writeln('<PARAM NAME="param3" VALUE="relativefilename">');
document.writeln('<PARAM NAME="value3" VALUE="true">');
document.writeln('<PARAM NAME="folderdepth" VALUE="-1">');
document.writeln('<PARAM NAME="param4" VALUE="account">');
document.writeln('<PARAM NAME="value4" VALUE="'+folderId+'">');
document.writeln('<PARAM NAME="transferui" VALUE="jfileupload.transfer.client.edesign.BatchTransferUI">');
//document.writeln('<PARAM NAME="transferuiresources" VALUE="i18n_pane">');
//document.writeln('<PARAM NAME="resources" VALUE="i18n_bar">');
document.writeln('<PARAM NAME="mode" VALUE="http">');
document.writeln('<PARAM NAME="post" VALUE="' + forwardUrl + '">');
//document.writeln('<PARAM NAME="overwrite" VALUE="false">');
//document.writeln('<PARAM NAME="resume" VALUE="true">');
//document.writeln('<PARAM NAME="chunkmode" VALUE="onfly">');
//document.writeln('<PARAM NAME="chunksize" VALUE="2048000">');
document.writeln('<PARAM NAME="shorterrorjs" VALUE="false">');
document.writeln('<PARAM NAME="param5" VALUE="httpmethod">');
document.writeln('<PARAM NAME="value5" VALUE="put">');
document.writeln('<PARAM NAME="whitelist" VALUE="' + whitelist + '">');