php - Using AJAX to send data to Coder Igniter controller function results in a 500 Internal Server Error -

i trying use ajax send data code igniter view controller handle data needed. i'm gathering data using jquery plugin (handsontable) , when user hits "save" button extracts required data table , executes ajax function.

$.ajax({     url: "/survey/save",     data: {"data": data},     type: "post", }); 

i able send regular .php file collects data $_post not controller.

public function save() {     $data = $this->input->post('data');      $myfile = "testfile.txt";     $fh = fopen($myfile, 'w') or die("can't open file");          ($i = 0, $size = count($data); $i < $size; ++$i) {         fwrite($fh, $data[$i][0]."\t".$data[$i][1]."\t".$data[$i][2]."\n");     }     fclose($fh); } 

the above code not want controller if can execute code, able wish.

i have feeling has url of ajax function extremely new of these languages , overlooking simple. please let me know if should include other code!

hey have change in ajax url format of url must absolute path e.g.

in view ajax should this

$.ajax({         url:'<?php echo site_url('survey/save'); ?>',         type: 'post',         data:  "data="+data,         beforesend:function(){                 //before send code e.g. put loader         },         success:function(result){              // success result code goes here         },         error:function(jqxhr, status, error){             if(status!='error')                 alert(error);            }     }); 

now in controller can data

$data=$this->input->post('data'); 

and 1 more thing have use relative path when using fopen e.g.

//you have used

$myfile = "testfile.txt";  //instead of have use  $myfile="./your_folder_name/your_file_name"; 

and can set in config.php

$config['base_url'] = '';