Javacript到节点

我目前正在使用一个表单构build器( https://github.com/kevinchappell/formBuilder ),它为我提供了一个GUI来构build自定义表单。 我得到的输出是以JSONforms存储在一个Javascriptvariables中。 我需要在后端使用这个Javascriptvariables来存储在我的MongoDB中。

我试图使用AJAX为此目的,但我未能检索的价值。 我的AJAX代码如下:

document.getElementById('getJSON').addEventListener('click', function() { var ans = formBuilder.actions.getData('json', true); $.ajax({ type: "POST", data: ans, url: "/j", success: function(data){ console.log(data); } }); document.forms["myForm"].submit(); 

而在服务器端:

  router.post('/j', function(req, res, next) { req.session.fdata = req.body; res.redirect('/log2'); }); 

我不断收到这个错误:

  Error: Can't set headers after they are sent. at validateHeader (_http_outgoing.js:504:11) at ServerResponse.setHeader (_http_outgoing.js:511:3) at ServerResponse.header (C:\Users\Abhishek\Basics\first-express\node_modules\express\lib\response.js:730:10) at ServerResponse.send (C:\Users\Abhishek\Basics\first-express\node_modules\express\lib\response.js:170:12) at done (C:\Users\Abhishek\Basics\first-express\node_modules\express\lib\response.js:967:10) at Object.exports.renderFile (C:\Users\Abhishek\Basics\first-express\node_modules\jade\lib\index.js:374:12) at View.exports.__express [as engine] (C:\Users\Abhishek\Basics\first-express\node_modules\jade\lib\index.js:417:11) at View.render (C:\Users\Abhishek\Basics\first-express\node_modules\express\lib\view.js:128:8) at tryRender (C:\Users\Abhishek\Basics\first-express\node_modules\express\lib\application.js:640:10) at Function.render (C:\Users\Abhishek\Basics\first-express\node_modules\express\lib\application.js:592:3) at ServerResponse.render (C:\Users\Abhishek\Basics\first-express\node_modules\express\lib\response.js:971:7) at C:\Users\Abhishek\Basics\first-express\app.js:50:7 at Layer.handle_error (C:\Users\Abhishek\Basics\first-express\node_modules\express\lib\router\layer.js:71:5) at trim_prefix (C:\Users\Abhishek\Basics\first-express\node_modules\express\lib\router\index.js:315:13) at C:\Users\Abhishek\Basics\first-express\node_modules\express\lib\router\index.js:284:7 at Function.process_params (C:\Users\Abhishek\Basics\first-express\node_modules\express\lib\router\index.js:335:12) 

我的/ log2路线是

 router.get('/log2', function(req, res, next) { res.render('log2',{ fdata: req.session.fdata}); res.session.fdata=null; });