unescape() is deprecated, do I need decodeURI()?

[csdude55]

I've been using this for years (decades?) to find the value of a cookie:

function getCookie(c_name) {
 if (document.cookie.length > 0) {
  c_start = document.cookie.indexOf(c_name + '=');

  if (c_start != -1) {
   c_start = c_start + c_name.length+1;
   c_end = document.cookie.indexOf(';',c_start);

   if (c_end == -1) c_end = document.cookie.length;

   return unescape(document.cookie.substring(c_start, c_end));
  }
 }

 return '';
}

I just discovered that unescape() is deprecated:

[developer.mozilla.org...]

But I honestly don't know why I used it in the first place.

Would you recommend using decodeURI() or decodeURIComponent() instead? What would be the danger of just returning document.cookie.substring(c_start, c_end)?