Check If a PHP Cookie Exists and If Not Set Its Value

Check if a PHP cookie exists and if not set its value

Answer

You can't according to the PHP manual:

Once the cookies have been set, they can be accessed on the next page
load with the $_COOKIE or $HTTP_COOKIE_VARS arrays.

This is because cookies are sent in response headers to the browser and the browser must then send them back with the next request. This is why they are only available on the second page load.

Work around

But you can work around it by also setting $_COOKIE when you call setcookie():

if(!isset($_COOKIE['lg'])) {
    setcookie('lg', 'ro');
    $_COOKIE['lg'] = 'ro';
}
echo $_COOKIE['lg'];

How would I test if a cookie is set using php and if it's not set do nothing

Use isset to see if the cookie exists.

if(isset($_COOKIE['cookie'])){
    $cookie = $_COOKIE['cookie'];
}
else{
    // Cookie is not set
}

Checking if Cookie is empty or set in php not working?

You need to use setcookie()

Example:

setcookie("uservalue", "some-value", time()+3600, "/", "example.com", 1);

After setting the cookie, you can check if it's empty:

if (!empty($_COOKIE["uservalue"])){
    echo "<span style='color: white'> cookie isn't empty </span>";
}

---

empty is true on the following conditions:

"" (an empty string)
0 (0 as an integer)
0.0 (0 as a float)
"0" (0 as a string)
NULL
FALSE
array() (an empty array)
var $var; (a variable declared, but without a value in a class)

Check if cookie is set

make a new page with this code

    if (isset($_SESSION['ID']))
{
        if (isset($_COOKIE['cookie'])
        {
        $ip = get_ip();
        $yourbrowser= $ua['name']. " " .$ua['version'];

        $req = $bdd->prepare('SELECT * FROM cookies WHERE hash_username = :hash, IP = :IP, browser = :browser');
        $req->execute(array('hash_username' => md5($_SESSION['username']), 'IP' => $ip, 'browser' => $yourbrowser));
            if ($req->fetch())
        {
            $_SESSION['ID'] = $data['ID'];
            $_SESSION['username'] = $data['username'];
            $_SESSION['stat'] = $data['stat'];
        }
        $req->closeCursor();
    }
}

and include it in every page . after that you will not need to write your code again and again.

Check if a PHP cookie exists not worked

force $_COOKIE['mycookie'] for affect immediatly

<?php
if (!empty($_POST['submits'])) {
    setcookie('mycookie', 'value', time()+ 36);
    $_COOKIE['mycookie'] = 'value'; // <----
}
?>

<form action="" method="post">
  <?php
    if (empty($_COOKIE['mycookie'])) {
        echo '<input type="submit" value="Up+1" id="submit" name="submits">';
    } else {
        echo 'NotSet';
    }
  ?>
</form>

PHP To check if cookie is there, equal to NULL, or exists

$_cookie should be caps. Change it to $_COOKIE and it should work.

Javascript - Check if cookie is set

Here is a function for get the cookie value in javascript.

mycookieValue = getCookie("mycookieName")

if(mycookieValue)
{
  //Your code here
}

function getCookie(name)
{
    var re = new RegExp(name + "=([^;]+)");
    var value = re.exec(document.cookie);
    return (value != null) ? unescape(value[1]) : null;
}

Check for Cookie existance, if yes do whatever, if no set a cookie

You can use getCookie and setCookie Functions

function setCookie(cname, cvalue, exdays) {
  var d = new Date();
  d.setTime(d.getTime() + (exdays*24*60*60*1000));
  var expires = "expires="+ d.toUTCString();
  document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}

function getCookie(cname) {
  var name = cname + "=";
  var decodedCookie = decodeURIComponent(document.cookie);
  var ca = decodedCookie.split(';');
  for(var i = 0; i <ca.length; i++) {
    var c = ca[i];
    while (c.charAt(0) == ' ') {
      c = c.substring(1);
    }
    if (c.indexOf(name) == 0) {
      return c.substring(name.length, c.length);
    }
  }
  return "";
}

Example

var user = getCookie("username");
  if (user != "") {
    alert("Welcome again " + user);
  } else {
    user = prompt("Please enter your name:", "");
    if (user != "" && user != null) {
      setCookie("username", user, 365);
    }
  }

Reference: W3Schools https://www.w3schools.com/js/tryit.asp?filename=tryjs_cookie_username

how to know a cookie is set or not in cakephp

@ sudhir
@ newRehtse

since when can use you methods in isset() or empty()?
thats news to me..^^

so correct would be

if ($this->Cookie->read('somevalue') !== null) {} 

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