Linking the items from drop down menu to the attachments

Hi, I have a drop down menu and want to link the subjects  from it to .pdf attachments in document. Bsically when I'm calling the items in drop down menu it's triggering to open the attached document. I've created the JS code for the single button: this.exportDataObject({ cName: "Doc_1", nLaunch: 2 }), and trying to make the same with drop down menu. Can someone help me with that?