How do you set a cookie to be accessible across the entire domain in Javascript

I suppose there should be a way to set a cookie to be accessible from the entire domain nevermind from 开发者_开发问答which directory you are setting the cookie.

Say in mypage.com/blue/index.php y set the cookie "colour=blue;" this way:

document.cookie = "colour" + "=" + "blue" 
    + "; expires=" + expireDate.toGMTString() 
    + "; path=/";

Using this code, the cookie retrieval function in mypage.com/home.php can't access the content of the cookie.

If it was just from first level directories that the cookie needs to be set, we would be ok by doing path=../ instead of path=/

But how do you go about writing generic code that sets a cookie that is accessible from any page in that domain not minding how deep in the file structure is the page the cookie is being set from?

Use path just like you did, but set an additional ;-delimited attribute "domain". If you start the domain value with a . it will allow any subdomains (.example.com would effectively allow *.example.com).

Full documentation for the various cookie options here