How do I pass have a Javascript script request a PHP page and pass data to it? How do I then have the PHP script pass data back to the Javascript script?
client.js:
data = {tohex: 4919, sum: [1, 3, 5]};
// how would this script pass data to server.php and access the response?
server.php:
$tohex = ... ; // How would this be set to data.tohex?
$sum = ...; // How would this be set to data.sum?
// How would this be sent to client.js?
array(base_convert($tohex, 16), array_sum($sum))
You can pass data from PHP to javascript but the only way to get data from javascript to PHP is via AJAX.
You can easily get the JavaScript variable value on the same page in PHP. Try the following codeL. <script> var res = "success"; </script> <? php echo "<script>document.
Besides, PHP and JavaScript similarities, these two languages are a powerful combination when used together. Large numbers of websites combine PHP and JavaScript – JavaScript for front-end and PHP for back-end as they offer much community support, various libraries, as well as a vast codebase of frameworks.
We can pass data from PHP to JavaScript in two ways depending on the situation. First, we can pass the data using the simple assignment operator if we want to perform the operation on the same page. Else we can pass data from PHP to JavaScript using Cookies. Cookie work in client-side.
Passing data from PHP is easy, you can generate JavaScript with it. The other way is a bit harder - you have to invoke the PHP script by a Javascript request.
An example (using traditional event registration model for simplicity):
<!-- headers etc. omitted -->
<script>
function callPHP(params) {
var httpc = new XMLHttpRequest(); // simplified for clarity
var url = "get_data.php";
httpc.open("POST", url, true); // sending as POST
httpc.onreadystatechange = function() { //Call a function when the state changes.
if(httpc.readyState == 4 && httpc.status == 200) { // complete and no errors
alert(httpc.responseText); // some processing here, or whatever you want to do with the response
}
};
httpc.send(params);
}
</script>
<a href="#" onclick="callPHP('lorem=ipsum&foo=bar')">call PHP script</a>
<!-- rest of document omitted -->
Whatever get_data.php
produces, that will appear in httpc.responseText. Error handling, event registration and cross-browser XMLHttpRequest compatibility are left as simple exercises to the reader ;)
See also Mozilla's documentation for further examples
I run into a similar issue the other day. Say, I want to pass data from client side to server and write the data into a log file. Here is my solution:
My simple client side code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js" type="text/javascript"></script>
<title>Test Page</title>
<script>
function passVal(){
var data = {
fn: "filename",
str: "this_is_a_dummy_test_string"
};
$.post("test.php", data);
}
passVal();
</script>
</head>
<body>
</body>
</html>
And php code on server side:
<?php
$fn = $_POST['fn'];
$str = $_POST['str'];
$file = fopen("/opt/lampp/htdocs/passVal/".$fn.".record","w");
echo fwrite($file,$str);
fclose($file);
?>
Hope this works for you and future readers!
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