title: backbonejs how to call function when page loaded
body: <p>I have function with the simple selector <code>$(.some-class)</code> not with 
  <code>this.$(.some-class)</code>. I call this function in the render. But this function cannot find the <code>.some-class</code>. As I understand I must call function when DOM is loaded. How can I do that?</p>
  
  <p>File with Backbone view:</p>
  
  <pre><code>var DocumentView = Backbone.View.extend({
    render: function(){
      someFunction('.some-class');
    },
  });
  </code></pre>
  
  <p>File with the function:</p>
  
  <pre><code>function someFunction(target) {
    $(target);
  }
  </code></pre>
  
  <p>I cannot find an element with class <code>'.some-class'</code>, with backbone, but when page is loaded I can do that.</p>