yep.js

$.ajax({ url: this.action+'.json',
         dataType: 'json',
         accepts: 'text/json',
         data: $(this).serialize(),
         type: 'post',
         success: function(data, textStatus, XMLHttpRequest) { ... }})

// this works in all browsers except IE.. when sent from IE the server thinks it's asking for a mimetype of image/gif
// i have tried all combinations of including and excluding "accepts", "dataType", and adding ".json" onto the end of the form action.