Sending a post request from Backbone.js is returning a cross domain error
<p>I'm using express.js as a backend and backbone.js as a front end and MongoDB as a database. I have no problem fetching single posts or collections of posts based on params I pass in, but whenever I try a POST request I get an error. I have tired to call .save() on my model but, I get a cross site domain error. 
Here is part of my code</p>

<pre><code>var Post = Backbone.Model.extend({
  url: "/posts/new"
});

var Posts = Backbone.Collection.extend({
  url: "/categories/all"
});

var PostView = Backbone.View.extend({
  model: new Post(),
  template: JST["post"],
  new_template: JST["new_post"],
  el: $(".page"),

  events: {
    "click .to_category": "updateCurrentCategory",
    "submit .new_post": "create"
  },

  create: function (e){
    e.preventDefault();
    showLoader();
    console.log("subbmited");
    this.model.save();
    hideLoader();
  }
}
</code></pre>