jQuery .post() method and codeigniter form_validation

jQuery .post() method and codeigniter form_validation

Hi !
I want to validate a form without refreshing the page using the .post() jQuery method. I use codeigniter for validation . Here is the jQuery code:

$(document).ready(function(){
$(".form_errors").hide();
$("#send").on("click",function(){ //the submit button has the id="send"
$(".form_errors").hide();  //these are <p> for each input to show the error
var user=$("input.box");
var data={};
var names=$("input.box").attr("name");
for(i=0;i<user.length;i++){
name=names[i];
value=user[i].val();
data.name=value;
}
$.post('ksite/account',
data,
function(result){
$("div.answer").html(result);
for(i=0;i<user.length;i++){
error_message=<?php echo form_error("?>names[i]<?php ");?>;
$("p#error_"+names[i]+".form_errors").html(error_message).show();
}
}
});
});

form_error is a CodeIgniter function.(I suppose someone who used ci is familiar with).

The form :
<p id="error_user" class="form_errors"></p>
<input type="text" class="box" name="user">
<p id="error_password" class="form_errors"></p>
<input type="password" class="box" name="password">
<input type="submit" id="send">

Is the form tag neccessary ? And if yes,do i have to mention action and method ?
Do I have to specify the type of the response?

And in ksite/account I do :

......
if(!this->form_validation->run(''account")){
    echo "The account couldn't be made";
}
else
{
  echo "The account was successfully created  ";
}
P.S.Although you may not be familiar with codeigniter,I would appreciate if someone coulf tell me if the code is correct and what improvements could be made .

Thanks a lot !