Faced a problem after installing Kaspersky Anti-Virus 2017 .
The site has a drop-down menu, implemented through js . It works fine, no errors.
But, after I set up an antivirus program for myself, when I go to the main page where this menu is located, now menu items that have nested sub-items (they turned around when hovering) are immediately displayed unfolded.
In the developer console through the browser I observe a number of errors:
Uncaught ReferenceError: jQuery is not defined - jquery.fancybox-1.3.4.pack.js: 46
Uncaught ReferenceError: jQuery is not defined - index.html: 1
Uncaught ReferenceError: jQuery is not defined - jquery.mousewheel-.0.4.pack.js: 14
Uncaught ReferenceError: jQuery is not defined index.html: 34
Uncaught ReferenceError: $ is not defined index.html: 95
Uncaught ReferenceError: $ is not defined index.html: 176
Uncaught ReferenceError: $ is not defined
onmouseover @ index.html: 269
I understand that Kaspersky from the client side somehow disrupts the work of js . This error is observed in all browsers (IE, Mozilla, Chrome, Opera).
Note: adding a site to a web antivirus exception does not help, because everything works fine only if you turn off KAV completely, if you enable any of the functions in KAV, an error occurs regardless of which protection (which module) was enabled.