Gmail user can not send this type of attachment from gmail.

Gmail by Google

A Millions of gmail user across the world will not be able to send .js file as attachment. The search engine Google announced this on G Suite Updates blog According to the company .js files are increasingly being used to spread malware.

Gmail currently restricts certain file attachment (e.g .msc, .bat, and exe) for security reasons, and starting on February 13, 2017, we willl not allow .js file attachment as well. 

The blog post also mension that for inbound mails, the sender will be receiving a bounce message explaining them why the mail was blocked and was not sent.The blog further adds that those who really need to send .js file can use Google Drive, Google Cloud Storage, or other storage solution to share or send their file.

Also Read : Google Renamed Google Keyboard To Gboard With Update To v6.0

Gmail currently restricts other file formats including .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 and .wsh.

Recently, a US judge ordered to google to comply with search warrants seeking customer email storage outside the United States. in court papers , Google said it sometimes breaks up email into pieces to improve its network's performance and did not necessarily know where particular emails might be stored.

source by: gadgetnow