How to set cookie secure flag using javascript

This cookie package is easy to use @ https://www.npmjs.com/package/js-cookie

 //to set cookie use
 Cookies.set('name', 'value', { expires: 7, path: '' });

 //to read the cookie, use
 Cookies.get('name'); // => 'value'

 //to delete cookie this
 Cookies.remove('name')

  //to set secure cookie this
 Cookies.set('name', 'value', { secure: true });

TL:DR

document.cookie = "tagname = test;secure";

You have to use HTTPS to set a secure attribute

The normal (or formal, maybe) name is attribute. Since the flag refers to other things.

More Info

Cookie attributes:

Secure - Cookie will be sent in HTTPS transmission only.

HttpOnly- Don't allow scripts to access cookie. You can set both of the Secure and HttpOnly.

Domain- specify the hosts to which the cookie will be sent.

Path - create scopes, cookie will be sent only if the path matches.

Expires - indicates the maximum lifetime of the cookie.

More details and practical usages. Check Testing_for_cookies_attributes_(OTG-SESS-002)

UPDATES The following contents expire in June 2, 2016.

Cookie Flags

Cookie flags are prefixes. At the moment, they are described in the RFC draft as a update to the RFC6265

These flags are used with the 'secure' attribute.

__Secure-

The dash is a part of the prefix. This flag tells the browser, the cookie should only be included in 'https'.

__Host-

A cookie with this flag

1. must not have 'domain' attribute, it will be only sent to the host which set it.

2. Must have a 'path' attribute, that is set to '/', because it will be sent to the host in every request from the host.

because the flag is called secure, not security:

document.cookie = "tagname = test;secure";