jQuery Ajax在codeigniter中

I am trying to use jQuery ajax in Codeigniter. In previous projects I already used jQuery ajax but this time I am getting problems. Below is my code

$.ajax({
  type:"POST",
  url:"<?php echo base_url()?>register",
  data:{
    name:$("#f_name").val()
  },
  cache:false,
  success:function(result){
    $("#registration_result").html(result);                  
    alert("success");
  },
  error:function(){
    alert("fail");
  }
});

Here the problem is even I am not getting the Error message "Fail". Please let me know if I am doing anything wrong here.

Please check your register page url, maybe the page is not found, so ajax fall into error-function,

  error:function(){
    alert("<?php echo base_url()?>register");
    alert("fail");
  }

when your ajax running it will alert "url register", then please open that url, to check if the page is exist or not.

If the register-page is not exist,

• Make sure register controller is exist

• Check value of "index_page" application/config/config.php

  $config['index_page'] = 'index.php';

If the value is "index.php", change your ajax-url into

url:"<?php echo base_url()?>index.php/register",