You have to insert a hidden input with the _token and later get that value as you do to get the other form fields in your ajax post.

<inputtype="hidden"name="_token"value="{{ csrf_token() }}"/>

An another method,

On your view you can set an object with the _token

<scripttype="text/javascript">var _globalObj ={{ json_encode(array('_token'=> csrf_token()))}}</script>

and later on your ajax call you can get the _token from the object like this:

var token = _globalObj._token;

and include it on your ajax post.

就是要加token...