In the past, hackers used other file types for attacking. Such as:
.ADE, .ADP, .BAT, .CHM, .CMD, .COM, .CPL, .EXE, .HTA, .INS, .ISP, .JAR, .JSE, .LIB, .LNK, .MDE, .MSC, .MSP, .MST, .PIF, .SCR, .SCT, .SHB, .SYS, .VB, .VBE, .VBS, .VXD, .WSC, .WSF, .WSH
After February 13th, if a user will try to add a .js file attachment to Gmail, he/she will get an error message saying that the attachment can’t be uploaded.
How to Send .js Files From Now On?