How to pass string from Webix textarea to Button's function

Here is my page:

<!DOCTYPE html>
<html>
    <head>
        <title>Loading from DB</title>
    <link rel="stylesheet" href="codebase/webix.css" type="text/css"> 
    <script src="codebase/webix.js" type="text/javascript"></script> 

    </head>
    <body>

<?php
$filename = getcwd() . "/test.txt";
echo $filename;
$line_i_am_looking_for = 5;
$lines = file( $filename , FILE_IGNORE_NEW_LINES );
$lines[$line_i_am_looking_for] = '6my modified line';
file_put_contents( $filename , implode( "\n", $lines ) );
?>



        <div class='header_comment'>Test Button</div>
        <div id="testB" style='height:600px'></div>
        <hr>

        <script type="text/javascript" charset="utf-8">

        webix.ready(function(){

          gridb = webix.ui({
                                container:"testB",
                 "view": "form",
  "elements": [
    {
      "view": "textarea",
      "name": "woNumber",
      "label": "",
      "width": 300,
      "height": 200,
      "options": [
        "onViewResize"
      ],
      "value": "",
      "placeholder": "WO number (separate with comma if several)",
      "labelPosition": "top"
    },
    {
      "view": "button",
      "name": "getWODetails",
      "label": "",
      "value": "Submit",
      "options": [
        "autowidth:true"
      ],
                on:{
                    onItemClick:function(id){
                        webix.message("Test");
                    }
                },
      "labelPosition": "top"

    },
    {
      "view": "button",
      "name": "getWODetails",
      "label": "",
      "value": "Passss",
      "options": [
        "autowidth:true"
      ],
                                on:{
                                        onItemClick:function($filename){
                                                webix.message($filename);
                                        }
                                },
      "labelPosition": "top"

    }

  ]
                        });     



        });


        </script>
    </body>
</html>

Now, I am trying to add below code to function to be able to add some string while pressing Passss button:

$filename = getcwd() . "/test.txt";
echo $filename;
$line_i_am_looking_for = 5;
$lines = file( $filename , FILE_IGNORE_NEW_LINES );
$lines[$line_i_am_looking_for] = '6my modified line';
file_put_contents( $filename , implode( "\n", $lines ) );

But if I am doing it like below sample it doesnt work:

on:{
    onItemClick:function($filename){
    $filename = getcwd() . "/test.txt";
    echo $filename;
    $line_i_am_looking_for = 5;
    $lines = file( $filename , FILE_IGNORE_NEW_LINES );
    $lines[$line_i_am_looking_for] = '6my modified line';
    file_put_contents( $filename , implode( "\n", $lines ) );
                                        }

Is there any clue how to achieve that?

Solution

You need to call a server side script from button's click. Something like next

on:{
    onItemClick:function(){
        webix.ajax().post("save.php");
    }
}

and now, in save.php you can place the necessary logic.

If necessary, you can send an extra parameters to the server side, by using second parameter of webix.ajax.post

on:{
    onItemClick:function(){
        //will be $_POST["some"] on a server-side
        webix.ajax().post("save.php", { some: this.getValue() });
    }
}