Question

How Can I delete cookie contains string

displayName

in name?
it is only one cookie with this string, but I don’t know all name, only the part?

Answer 1

If you don’t know the full name of the cookie, you could easily find out by inspecting the entire cookie collection:

var names = document.cookie.split(';')
   .map(function(c) { return c.split('=')[0]; })
   .filter(function(c) { return c.indexOf('displayName') > -1; });

Here, names would contain all the cookies with displayName in their name. If you’re sure that’ll only ever be one, go ahead and delete names[0].