title: javascript couldn't apply index of on a string
body: <p>This is my code: </p>
  
  <p>I take the value of a <code>td</code> like this:</p>
  
  <pre><code>$transactionIDFilterValue = $("#transactionIDFilter").val()
  </code></pre>
  
  <p>Then I compare it to another value like this:</p>
  
  <pre><code>function notGoodTransactionID(value, filterValue){
      index = 0;
      if (value.indexOf(filterValue) != -1) {
          return false;
      }
      return true;
  }
  </code></pre>
  
  <p>I am getting error that </p>
  
  <blockquote>
    <p>Uncaught TypeError: value.indexOf is not a function</p>
  </blockquote>
  
  <p>Why is that?</p>