When i selected some portion of the map in QGIS, in the attribute table the selected features gets highlighted...
How to export the highlighted features from attribute table to an excel file automatically..?
Simply select the features on the map and use copy-paste (Ctrl + C , Ctrl + V) to copy the data into a text editor or Excel.
Or: After you highlighted them->right click on the Layer->Save Selction as->In the Drop-down menu you can choose csv(comma seperated value/ excel) format there. Done
Another easy solution might be the use of the "mmqgis" plugin. You can find it directly via the plugin downloader.
After loading you will find in the menu Plugins->mmqgis->Transfer a clickable dialog to export shape attribute tables to csv data. You can even export whole geometries.
You can select the features, go to the attribute table then highlight the selected features that you want from that selection and then right click in the attribute table and hit "re-select highlighted" giving you your new selection which you can now export and save.
Hope that is clear/helps