title: JavaScript: JSLint error "The body of a for in should be wrapped in an if statement to filter unwanted properties from the prototype"
body: <p>I'm using the <strong><a href="http://JSLint.com">JSLint</a></strong> tool to ensure my JavaScript is "strict".</p>
  
  <p>I'm receiving the following error but don't understand how to fix it:</p>
  
  <pre><code>The body of a for in should be wrapped in an if statement to filter unwanted properties from the prototype
  </code></pre>
  
  <p>For the following code:</p>
  
  <pre><code>for (var i in keypairs) {
      ...
  }
  </code></pre>
  
  <p>Anyone have any ideas how to fix this to that it's JavaScript "strict" and won't be flagged by JSLint</p>