File downloading with Ajax problem

Hi guys,

I'm new in mvc. I have faced problem with downloading

My Ajax code is

$.ajax({
    type:"POST",
    url: base_url +'/Home/IndexSpecification',
    data:{ option_id :2},//dataType: 'json', encode: true,
    async:false,
    cache:false,
    success: function (data, status, jqXHR){
        console.log(data);},
    error: function (jqXHR, textStatus, errorThrown){if(typeof(console)!='undefined'){
            alert("oooppss");}else{
            alert("error");}}});

Downloading not working and not even returning any error. Anyone please help. Thanks!