TypeError: 'append' called on an object that does not implement interface FormData.

var name=$('#element_name').val();
    var ofile=document.getElementById('image').files[0];
    var formdata;
        if(FormData)
        {
            formdata=new FormData();
            formdata.append("image",ofile);
        }
    formdata.append("element_name",name);
    $.ajax({
        url:'elements/save_elements',
        data:formdata,
        type:'POST',
        success:function(res)
        {
            $('#response').html(res);
        },
        error:function(xhr,rrr,error)
        {
            alert(error);
        }
    });