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<?php
    // Connect to database server
    mysql_connect("192.168.1.101/phpmyadmin/", "root", "praticas") or die (mysql_error ());

    // Select database
    mysql_select_db("logs_history") or die(mysql_error());

    //---> at this point, I want yo pull a VALUE from a column called potencia_ativa and insert in 
    // the code JS below


      mysql_query($strSQL);
    // Close the database connection
    mysql_close();
    ?>

//JS code-------------------------------------------------------------------------------------------

<div id="graphHolder" style="height:75%;width:100%"></div>
<script type="text/javascript">

setInterval(
            function() {

                var d1 = [];
                for (var i = 0; i < parseInt(document.getElementById('number').value,10); i += 0.5) {
                    d1.push([  //----------> pull the value from the php/DB as a FLOAT
                        ]);
                }

                $.plot("#graphHolder", [{
                        label: "Label",
            data: d1,
                        lines: { show: true, fill: true }
                }
                ]);
            }, 1000);
</script>
Harry Pehkonen
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Henrique Alvim
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  • sorry, can you explain clearer? i don't get it – stormrage Nov 12 '14 at 13:55
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    Please, [don't use `mysql_*` functions](http://stackoverflow.com/questions/12859942/why-shouldnt-i-use-mysql-functions-in-php), They are no longer maintained and are [officially deprecated](https://wiki.php.net/rfc/mysql_deprecation). Learn about [prepared statements](http://en.wikipedia.org/wiki/Prepared_statement) instead, and use [PDO](http://us1.php.net/pdo) or [MySQLi](http://us1.php.net/mysqli). You will also want to [Prevent SQL Injection!](http://stackoverflow.com/questions/60174/how-can-i-prevent-sql-injection-in-php) – Jay Blanchard Nov 12 '14 at 13:55
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    You can't insert data into a database directly from javascript. You should do this with an AJAX request. – S.Pols Nov 12 '14 at 13:57
  • I'm sorry for the mistakes, I'm a beginner ate programming. The comments on the code is what I'm trying to do – Henrique Alvim Nov 12 '14 at 14:06

2 Answers2

0

Remember, PHP executes on the server and GENERATES the page that runs the Javascript on the client. Putting a value from PHP into the JS code is as simple as:

<script>
   var foo = <?php echo json_encode('bar'); ?>;
</script>

If you need to send the PHP data over AFTER the page was generated and already send to the client, then you need to have the client execute an AJAX request to fetch that data from the server. Once PHP has shoved the page out the door, it's basically done and can't "reach out" to the client to do updates on its own.

Also: Note the use of json_encode(). You should NEVER dump output from PHP directly into a Javascript context without it. Anything else puts you at risk of generating JS syntax errors, which will kill the entire JS code block.

Marc B
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0

Why are you using Interval? Are you trying to update the displaying page data/value automatically after some time passed? That won't work, because if anything changes in database, It won't change in the displaying page, unless you use AJAX to call your php script and return some values, and then, change in the displaying page.

To get a value from PHP script to JAVASCRIPT, you just need to use the php clausule;

   var test = <?php echo $variable; ?>
   // echo for strings, ints, floats.
   // print_r for arrays.

Of course, if your PHP script already injected the data into the page/the data is in the same page you're using JAVASCRIPT, assuming that you have already fetched the data, handled it and etc.

Kelwen Souza
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