How to inject javascript code that uses php variables into php page - php

Question

I created a php page and javascript code that contains some variables from the PHP page, this is a code that inserts php variables into the database using Javascript :
<?php
$id = "Kevin";
$user = "Calvin";
?>
<!-- include jquery library file-->
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<!-- The ajax/jquery stuff -->
<script type="text/javascript">
function send(e){
if(e.keyCode == 13 && !e.shiftKey){
$(document).ready(function(){
//Get the input data using the post method when Push into mysql is clicked .. we pull it using the id fields of ID, Name and Email respectively...
//Get values of the input fields and store it into the variables.
var msg=$("#reply").val();
clear();
//here you start PHP->>
//here we put the PHP Variables ^^^^^^^^^///\\\
//use the $.post() method to call insert.php file.. this is the ajax request
$.post('full.php', {msgg: msg, from: <?php echo json_encode($id); ?>, to: <?php echo json_encode($user); ?>},
function(data){
$("#message").html(data);
$("#message").hide();
$("#message").fadeIn(200);
});
function clear() {
$("#myre :input").each( function() {
$(this) .val('');
});
}
});
}
}
</script>
and in the full.php page
<?php
mysql_connect("localhost","root","");
mysql_select_db("db");
$to=mysql_real_escape_string($_POST['to']);
$from=mysql_real_escape_string($_POST['from']);
$msg=mysql_real_escape_string($_POST['msgg']);
$to = mysql_real_escape_string($to);
$from = mysql_real_escape_string($from);
$msg = mysql_real_escape_string($msg);
if(empty($msg)){
exit();
}
$query=mysql_query("INSERT INTO `message`(`user`,`who`,`message`) VALUES ('$to','$from','$msg')");
if($query){
echo "Perfect!";
}else{
echo "Failed!!";
?>
so is there any way to put the Javascript code into another page and inject it using ajax?

Answer 1

Assign PHP variable's value to java script variable :
<script type="text/javascript">
var json{
"id":<?php echo $id;?>,
"user" : "<?php echo $user;?>"
};
</script>
Change this line from your code :
$.post('full.php', {msgg: msg, from: json.id, to: json.user}
Now you'll have separate js file like:
function send(e){
if(e.keyCode == 13 && !e.shiftKey){
$(document).ready(function(){
//Get the input data using the post method when Push into mysql is clicked .. we pull it using the id fields of ID, Name and Email respectively...
//Get values of the input fields and store it into the variables.
var msg=$("#reply").val();
clear();
//here you start PHP->>
//here we put the PHP Variables ^^^^^^^^^///\\\
//use the $.post() method to call insert.php file.. this is the ajax request
$.post('full.php', {msgg: msg, from: json.id, to: json.user},
function(data){
$("#message").html(data);
$("#message").hide();
$("#message").fadeIn(200);
});
function clear() {
$("#myre :input").each( function() {
$(this) .val('');
});
}
});
}
}
Say this file is myjs.js now include it in php file:
<script type="text/javascript" src="myjs.js" />