javascript - jQuery not sending JSON on AJAX POST request -

i little confused here,i trying post data node js server using following code:

$.ajax({type:'post',         url:'/map',         data:'type=line&geometry='+str,         success:function(msg)         {           console.log(msg);         },         datatype:'json'          }); 

this result here:

 { type: 'line', geometry: 'b~cqcge{b[mv|q@xnyc' } 

this not json.i had tried use contenttype , this:

$.ajax({type:'post',         url:'/map',         data:{type:'line',geometry:str},         success:function(msg)         {             console.log(msg);         },         datatype:'json',         contenttype:"application/json"       }); 

even sent data without change.i have tried above method using data string first one.i have tried setting processdata false along methods in code blocks.

it important me data in json , use ajax because trying insert mongodb node js using mongojs , fails

actually datatype has nothing input rather output.

instead want stringify input data , send down single variable backend can decode it:

$.ajax({type:'post',     url:'/map',     data: {data: json.stringify({type: 'line', geometry: str})},     success:function(msg)     {        console.log(msg);     },     datatype:'json'      }); 

that way in backend decode data , should functioning object json.

note need json class this, jquery not include ability default: https://github.com/douglascrockford/json-js