javascript - When a cookie is sent via http header to a browser will it be added to the client browser? -

i trying make connection api. when call method api, respond cookie value sent via http headers.

will header automatically added client "my browser?" or have parse request first , create cookie using setcookie?

if not add cookies automatically, there way so?

it'll handled automatically http client (you don't need set manually). server should respond set-cookie header (not cookie), client save cookie, , send on next requests.

setting cookie

cookies set using http set-cookie header, sent in http response. header instructs browser store cookie , send in future requests server (the browser will, of course, ignore header if not support cookies or has disabled cookies).

as example, browser sends first request homepage of www.example.org website:

get /index.html http/1.1 host: www.example.org ... 

the server responds 2 set-cookie headers:

http/1.0 200 ok content-type: text/html set-cookie: theme=light set-cookie: sessiontoken=abc123; expires=wed, 09 jun 2021 10:18:14 gmt ... 

the server's http response contains contents of website's homepage. instructs browser set 2 cookies. first, "theme", considered "session" cookie, since not have expires or max-age attribute. session cookies typically deleted browser when browser closes. second, "sessiontoken" contains "expires" attribute, instructs browser delete cookie @ specific date , time.

next, browser sends request visit spec.html page on website. request contains cookie header, contains 2 cookies server instructed browser set.

get /spec.html http/1.1 host: www.example.org cookie: theme=light; sessiontoken=abc123 ... 

this way, server knows request related previous one. server answer sending requested page, , possibly adding other cookies using set-cookie header.

the value of cookie can modified server including set-cookie header in response page request. browser replaces old value new value.

the value of cookie may consist of printable ascii character (! through ~, unicode \u0021through \u007e) excluding , , ; , excluding whitespace. name of cookie excludes same characters, =, since delimiter between name , value. cookie standard rfc 2965 more limiting not implemented browsers.

the term "cookie crumb" used refer cookie's name-value pair.

cookies can set scripting languages such javascript run within browser. in javascript, object document.cookie used purpose. example, instruction document.cookie = "temperature=20" creates cookie of name "temperature" , value "20".

see wikipedia page