javascript - Ajax request, null data, path to the server rails -

i have client request ajax, final url /promotion?mtd, log tell me parameter mtd = null. should promo = mtd, need data passing in url.

ajax:

var promo = document.getelementbyid('data-select').value;     $.ajax({         type: 'get',         url: '/promotion',         data: promo,         datatype: 'json',         success: function(data){           alert(data);         }     });  

log/development.log:

started "/promotion?mtd" 127.0.0.1 @ 2015-04-14 16:32:34 -0430 processing promoscontroller#get_percent json   parameters: {"mtd"=>nil} 

var promo = document.getelementbyid('data-select').value;     $.ajax({         type: 'get',         url: '/promotion',         data: {"promo" : promo},         datatype: 'json',         success: function(data){           alert(data);         }     });