John Davidson

Message:

I have this code:

<script type="text/javascript">

    var foo = 'bar';

    <?php

        file_put_contents('foo.txt', ' + foo + ');

    ?>



    var baz = <?php echo 42; ?>;

    alert(baz);

</script>

Why does this not write "bar" into my text file, but alerts "42"?

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NB: Earlier revisions of this question were explicitly about PHP on the server and JavaScript on the client. The essential nature of the problem and solutions is the same for any pair of languages when one is running on the client and the other on the server (even if they are the same language). Please take this in to account when you see answers talking about specific languages.

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My Answer:
Client-side programming refers to code that is executed on the user's browser, while server-side programming refers to code that is executed on the server.

In client-side programming, the code is written in languages such as HTML, CSS, and JavaScript and is executed on the user's browser. This type of programming is used to create interactive web pages and provide a better user experience.

On the other hand, server-side programming involves languages such as PHP, Python, and Ruby, and is executed on the server. This type of programming is used to process data, handle requests from clients, and interact with databases.

In the code you provided, it appears to be JavaScript code, which is typically used for client-side programming.