PHP：从case语句回应JQuery Alert

Question

I am trying to echo a JQuery alert from PHP. The method I am using is to echo the entire script tags and then the JQuery within it. JQuery is working because alerts elsewhere work. the JQuery library is loaded before the code i am trying so it is not that.

below is my current statement:

date_default_timezone_set('Europe/London'); #server timezone
    $now = date('His'); #current time
    $cl = '173000'; #closing time
    $op = '084500'; #opening time

    switch (true) {
        case $now < $cl && $now > $op:
            echo "open
            <script type='text/javascript'>
                $(document).ready(function(){
                    alert('open');
                });
            </script>
            ";
            break;

        case $now > $cl && $now < $op:
            echo 'closed';
            break;

        default:
            echo("neither closed nor open.  dun dun duuuuun");
            break;
    }

I know the statement is working to some extent because the open string is displayed. I also see the script tags yet they don't seem to execute see below:

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This image shows that the open text just before the script is echo'd into the page

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This image shows that the script tag is put into the page but is not executed

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Update:

The answer was that JQuery hadn't actually loaded like i thought it had. the version number was wrong. for some reason it was:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.4.3/jquery.min.js"></script>

I have now changed it to:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2/jquery.min.js"></script>

the reason I left the 2.x.x out is because the hosted library will choose the most up to date version of 2 now.

Answer 1

Are you sure you have jQuery loaded at that moment you want to alert? By the way, If you want to just alert something, you don't really need jQuery, just use:

<script>alert('open');</script>