Use PHP file in Javascript

Question

I have a PHP file contain some calculation. Now, I want to integrate the calculation into javascript in another file. How i can pass the variable in javascript to do calculation inside php?

this is my javascript code:

 $("#upload").on("click", function(){
    var csv = $('#csv');
    var csvFile = csv[0].files[0];
    var ext = csv.val().split(".").pop().toLowerCase();

    if($.inArray(ext, ["csv"]) === -1){
        alert('upload csv');
        return false;
    }
    if(csvFile != undefined){
        reader = new FileReader();
        reader.onload = function(e){

            csvResult = e.target.result.split(/\r|\n|\r\n/);
            
            var temp=[];
            for(i=0;i< csvResult.length; i++){
                if(csvResult[i] != "" && csvResult[i] != null){
                var data = csvResult[i].split(",");
                var rssi = data[0];
                var distance = data[1];
                var rssisample = 8;
                    if(distance == 1){
                      //need to insert calculation method from php



                        temp.push(rssi);
                    }   

                }
            }

I have php file name myphpfile.php. So, I want to use variable and value from javascript to perform calculation in php file and return back to javascript. Please help me on this

This is my some part of php file. eg: myphpfile.php

    <?php

// $arrTimeRSSI will read from javascript before perform this calculation


//calculate mean X using array_sum() method
$avgRSSI = array_sum($arrTimeRSSI)/($num_of_elements); 

function StandardDeviation($arrTimeRSSI){
    global $num_of_elements;
    global $avgRSSI;

    $variance = 0.0;
   
    foreach($arrTimeRSSI as $x){
        //sum of squares of difference between all numbers and mean X
        $variance += pow(($x - $avgRSSI), 2);
       
    }
    $newElements = $num_of_elements - 1;
    return (float)sqrt($variance/$newElements); 

} ?>

Answer 1

It is not that simple because PHP is executed on the server and JavaScript by the client. You have to use ajax to send your request with data to a php script (to the server) and get the response back to the client.

This is an example how your JavaScript can look like:

$("#upload").on("click", function(){
    var csv = $('#csv');
    var csvFile = csv[0].files[0];
    var ext = csv.val().split(".").pop().toLowerCase();

    if($.inArray(ext, ["csv"]) === -1){
        alert('upload csv');
        return false;
    }
    if(csvFile != undefined){
        reader = new FileReader();
        reader.onload = function(e){

            csvResult = e.target.result.split(/\r|\n|\r\n/);
            
            var temp=[];
            for(i=0;i< csvResult.length; i++){
                if(csvResult[i] != "" && csvResult[i] != null){
                var data = csvResult[i].split(",");
                var rssi = data[0];
                var distance = data[1];
                var rssisample = 8;
                    if(distance == 1){
                        $.ajax({
                            url: '/path/to/phpfile.php',
                            type: 'post',

                            // transmit your data
                            data: {number1: '15', number2: '15'},

                            success: function (response) {
                                // handle the response
                                // response should contain 225 in this example
                            }
                        });
                        temp.push(rssi);
                    }   

                }
            }
        }
    }
});

And this is how your PHP file at /path/to/phpfile.php could look like:

// do your calculations here and echo it
echo intval($_POST['number1']) * intval($_POST['number2']);

Another method is to make a php file and embed your javascript in it. But this solution does not allow you to transfer data from javascript to php. Because the php function is executed on the server and the javascript (with the calculated part) is send to the client after that. Like this example:

<?php 

// declare your php function here
function calculate() {
    return;
}

?>

<script>
$("#upload").on("click", function(){
    var csv = $('#csv');
    var csvFile = csv[0].files[0];
    var ext = csv.val().split(".").pop().toLowerCase();

    if($.inArray(ext, ["csv"]) === -1){
        alert('upload csv');
        return false;
    }
    if(csvFile != undefined){
        reader = new FileReader();
        reader.onload = function(e){

            csvResult = e.target.result.split(/\r|\n|\r\n/);
            
            var temp=[];
            for(i=0;i< csvResult.length; i++){
                if(csvResult[i] != "" && csvResult[i] != null){
                var data = csvResult[i].split(",");
                var rssi = data[0];
                var distance = data[1];
                var rssisample = 8;
                    if(distance == 1){
                        var calculation = <?php echo calculate(); ?>
                        temp.push(rssi);
                    }
                }
            }
        }
    }
});
</script>

Answer 2

this can be done by creating a formdata and pass it to the php file which on it returns values. In my experience it is best to pass json values and return them from the php file as well. javascript function:

function example(){
  var form_data = new FormData();
  form_data.append("Variable1ToPass","test1");
  form_data.append("Variable2ToPass","test2");
  $.ajax({
    url: '/ThePhpFileYourReferTo.php',
    type: 'POST',
    dataType: 'json',
    cache: false,
    async: false,
    data: form_data,
    contentType: false,
    processData: false,
    error: function(ReturnData){
      //here do the error handling
      console.log(ReturnData);
      return;
    },
    success: function(ReturnData) {
      console.log(ReturnData.ResultOfCalculation);
      return;
    }
  });
}

In the php file (ThePhpFileYourReferTo.php):

$DataToReturn = [];
$DataToReturn['SubmittedValue'] = $_POST;
$Variable2ToPass = $_POST['Variable2ToPass'];
$Variable2ToPass = $_POST['Variable2ToPass'];
//here do the calculation and write in the return variable
$DataToReturn['ResultOfCalculation'] = "OK DONE";
header('Content-type: application/json');
echo json_encode($DataToReturn);