Adobe Acrobat Pro JavaScript to detect when a Windows dialog box cancelled

Using Adobe Acrobat Pro javascript.  Need to detect when user clicks “Cancel” in Windows file dialog box triggered by adobe javascript importAnFDF() command.   

Using this code :

var noCatch = 0;
try{
importAnFDF();

} catch (err) {
app.alert("Import of Saved SGS File Cancelled by USER",3);
noCatch = 1;}

if(noCatch==0){
app.alert("File Imported",3);
}
 

// Code returns “File imported” when user actually cancelled the Windows dialog box.