function customer_details()
{
    $cus_id = $this->input->get('cus_id');
    $this->db->select('CustomerName,Phone,CompanyName,CustomerType,CallNotes,CallStatus,CustomerEmail,EntryDate,LastCalled');
    $this->db->from('agent_cdr');
    $this->db->where('id',"$cus_id");
    $query = $this->db->get();
    $ret = $query->row();
    echo json_encode($ret);

}

var response  = jQuery.trim(xmlhttp.responseText);
//console.log(response);
var arr = JSON.parse(response);
var arr = $.map(arr, function(el) { return el; })
console.log(arr) ;
var output="<ul>";
$.each( arr, function( key, value ) {
//alert( key + ": " + value );
if((value.length)>1){
  output+="<li>" + value + "</li>";
}
});
output+="</ul>";
$('#cus_details').html(output);

0: "Nitin Tomar"
1: "7010010001"
2: "Infosys"
3: "VIMP"
4: "closed"
5: "ntomar@gmail.com"

CallNotes: null
CallStatus: "closed"
CompanyName: "Infosys"
CustomerEmail: "ntomar@gmail.com"
CustomerName: "Nitin Tomar"
CustomerType: "VIMP"
EntryDate: "2015-09-05 17:18:53"
LastCalled: null
Phone: "7010010001"