How do I set path while saving a cookie value in JavaScript?

simply: document.cookie="name=value;path=/";

There is a negative point to it

Now, the cookie will be available to all directories on the domain it is set from. If the website is just one of many at that domain, it’s best not to do this because everyone else will also have access to your cookie information.

For access cookie in whole app (use path=/):

function createCookie(name,value,days) {
    if (days) {
        var date = new Date();
        date.setTime(date.getTime()+(days*24*60*60*1000));
        var expires = "; expires="+date.toGMTString();
    }
    else var expires = "";
    document.cookie = name+"="+value+expires+"; path=/"; 
}

Note:

If you set path=/,
Now the cookie is available for whole application/domain. If you not specify the path then current cookie is save just for the current page you can't access it on another page(s).

For more info read- http://www.quirksmode.org/js/cookies.html (Domain and path part)

If you use cookies in jquery by plugin jquery-cookie:

$.cookie('name', 'value', { expires: 7, path: '/' });
//or
$.cookie('name', 'value', { path: '/' });

document.cookie = "cookiename=Some Name; path=/";

This will do