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Editorial Team
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Asked: 2026-06-05T14:35:55+00:00

i’ve got a slight problem with JS enabled detection. not too big, because i

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i’ve got a slight problem with JS enabled detection.
not too big, because i know i’m on the right track.
but here’s my deal:

when i try to set a cookie in JS (jQuery) using this code

$(window).load(function(){
    $.cookies.set('c_jsEnabled', 'true');
});

or just in plain JS using this code

function setCookie()
{
    document.cookie='c_jsEnabled=true';
}
<body onload="setCookie();">

and then try to detect it in PHP using this code

if($_COOKIE['c_jsEnabled'] == 'true')
{
    if(file_exists('./main.php'))
    {
        require_once ('./main.php');
    }
    echo getIndex();
}
else 
{
    if(file_exists('./noJS.php'))
    {
        require_once ('./noJS.php');
    }
    echo getIndex();
}
setcookie('c_jsEnabled', '');

it takes 2 page refreshes to actually get the right value into PHP.
my guess is that this bascially means that the PHP script is executed before the JS function is fired.
could this be because all codes shown above are in the same script (index.php)?

This is kind of a problem for me, because i want to prevent people from using my website when they have JS disabled.

is there a way to set the cookie before php tries to get the cookie variable?

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1 Answer

  1. Editorial Team

    PHP only sends the cookie header when content is sent to the browser. Javascript then executes after that, so you would need a second load of the page to detect the cookie.

    This can trigger infinite redirection loops (especially if the user has cookies disabled), so be careful.

    To disable the site to users without Javascript, consider the following.

    <div id="noscript" style="width:100%; height:100%; z-index:999; position:absoloute; top:0px; left:0px; background-color:#CC9900; display:block">
Please Enable Javascript!</div>
<script type="text/javascript">
document.getElementById('noscript').style.display = 'none';
</script>

    I find the <noscript> tag is unreliable (there was a bug in iOS causing it to only show when there was Javascript, if I remember correctly).

    A second option:
    You can have the PHP check for a cookie. If it isn’t set, have it redirect (header("Location: aaa.html");) to a page with the Javascript to set the cookie and redirect back. (Alternatively, have the PHP output Javascript to set the cookie reload the page.) You then only have to worry about users who “spoof” the cookie, although you will also lock out users who have cookies disabled.

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