posting a variable from javascript button to php with mysql

Question

I'm quite new to PHP and Javascript. I am trying to get a variable from a google maps API marker with an option to delete the marker and its information from a MySQL database. No errors are being generated, however the row is not being deleted. I suppose that the problem is with the POST. Below is the code I have related to this matter:

var html = "<b>" + name + "</b> <br/>" + location + "<br/> <br/> <input type='button' value='Get Directions from your Current Position' onclick=getDirections()/> <br> <input type='button' name = 'remove' value='Remove Pointer' onclick=removePointer("+name+")/>";

That is the line where I am calling the removePointer function, passing 'name' as a parameter

function removePointer(name){
    var nameSend = name;
    $.post("index.php", {variableName: nameSend});
    <?php
        $mysql_host = "xxxx";
        $mysql_database = "xxxx";
        $mysql_user = "xxxx";
        $mysql_password = "xxxx";

        $link = mysql_connect($mysql_host, $mysql_user, $mysql_password);
        if (!$link) {
            die('Could not connect: ' . mysql_error());
        }

        mysql_select_db($mysql_database) or die(mysql_error());

        $removeName = $_POST['variableName'];
        mysql_query(("DELETE FROM markers WHERE Name='" . $removeName . "'"),$link) or die ("Markers Table Error: " . mysql_error());
    ?>
}

That is the removePointer function, where it should get the javascript variable, post it, and a PHP block to get the post and remove the MySQL row accordingly.

Thanks in advance for any help!

Answer 1

In your case, Javascript is something that will run in the user's browser while PHP is something that will run on the server (which will need to be able to talk to the database server). That is, you cannot embed PHP inside of a Javascript function and expect the PHP to be run - web browsers do not execute PHP. Further, you NEVER want to put any sensitive information into Javascript that will be running in a browser (such as MySQL credentials), because it will be visible to anyone who loads that Javascript.

You will need to create a server-side PHP script that Javascript will communicate with. Javascript could make an AJAX request to the PHP script, POSTing the data you wish the PHP to take action on. In this case, the removePointer() function could post the marker name to the PHP script, which would then remove it from the database.

To make life easier, you might consider using a Javascript library such as jQuery, which can greatly simplify making Ajax requests.

Answer 2

you cannot post just to your index.php page. create a new one "del.php", put your php code there, and post to that page:

index.php

function removePointer(name){
  var nameSend = name;
  $.post("del.php", {variableName: nameSend}); 
}

del.php

<?php
    $mysql_host = "xxxx";
    $mysql_database = "xxxx";
    $mysql_user = "xxxx";
    $mysql_password = "xxxx";

    $link = mysql_connect($mysql_host, $mysql_user, $mysql_password);
    if (!$link) {
        die('Could not connect: ' . mysql_error());
    }

    mysql_select_db($mysql_database) or die(mysql_error());

    $removeName = $_POST['variableName'];
    mysql_query(("DELETE FROM markers WHERE Name='" . $removeName . "'"),$link) or die ("Markers Table Error: " . mysql_error());
?>

of course im no php-expert, and that is for sure not the optimal way to do ajax requests, but i hope you understand the concept of ajax a little bit better know...