I found trojan on my website by AVG antivirus.I asked server manager to scan and delete it.they did it.I asked them to install antivirus to prevent future attacks.they said that .js files have java scripts which might be the a style sheet coding. Sometimes the coding style/method might be vulnerable for the server. Antivirus on the server won't be able to detect it. We can enable KasperSky Antivirus to check it but not sure about it.
what do you think? isn`t there a good antivirus? I do worry about my server