How to use JavaScript variable in PHP? - php

Question

I am trying this code:
<script type="text/javascript">
for (i = 0; i < 5; i++) {
for (x = 0; x < 1; x++) {
$("#one" + i).html("<?php echo $arr["+i+"]["+x+"] ?>");
$("#two" + i).html("<?php echo $arr["+i+"]["+x+1+"] ?>");
};
};
</script>
No error is showed, but content also not.
How can I use the increment variable of JavaScript in PHP code?
Thanks

Answer 1

You may make your PHP-array accessible to JS(store it as a js-variable) :
<script type="text/javascript">
var arr=<?php echo json_encode($arr); ?>;
for (i = 0; i < arr.length; i++) {
for (x = 0; x < 1; x++) {
$("#one" + i).html(arr[i][x]);
$("#two" + i).html(arr[i][x+1]);
};
};
</script>

Answer 2

You cannot do this.
Javascript runs on the client, which is after all PHP code has executed.
Why don't you write the loop in PHP instead? For example,
<script type="text/javascript">
<?php
for ($i = 0; $i < 5; $i++) {
for ($x = 0; $x < 1; $x++) {
printf('$("#one%s").html("%s");', $i, $arr[$i][$x]);
printf('$("#two%s").html("%s");', $i, $arr[$i][$x + 1]);
};
};
?>
</script>

Answer 3

Ok, I try to give you a short question..althought it may be very long.
PHP it's a Server-side scripting language, while javascript it's a Client-side one.
That's mean that the php code is interpreted and executeted in the server (e.g. Apache), and the javascript code is executed inside the browser itself.
So, there is no way you can execute php code inside of your brower.
for the code you have written you can simpli transform the two for javascript iteration in php. If you actually need to print something in php given a javascript variable you should do an AJAX request to a php page that recive your javascript value and returns back the php-calculated values you need.
Please have a look at those references as a start:
http://en.wikipedia.org/wiki/Server-side_scripting
http://en.wikipedia.org/wiki/Client-side_scripting
http://en.wikipedia.org/wiki/Ajax_(programming)

Answer 4

<?php is interpreted by the php interpreter. If you don't have this block in an actual php file, then that means you are executing in the context of the browser. The browser doesn't know about php, only your web server. Thus, the browser will interpret <?php as an HTML element, which doesn't exist.
You need to move your entire block into a php file, like so:
myFile.php
==========
<?php
$arr = array(...);
$arrLen = count($arr);
$output = '<script type="text/javascript">';
for ($i=0; $i<$arrLen; $i++) { // notice this is in php, not js
$output .= '$("#one"'.$i.').html("'.$arr[$i][0].'");';
$output .= '$("#two"'.$i.').html("'.$arr[$i][1].'");';
}
$output .= '</script>';
echo $output;
?>