title: How to insert text into a form with JavaScript
body: <p>I'm trying to create a simple extension for personal use. It's partially from laziness, and partially from an urge to learn. I've never made extensions before, but I've been looking at the documentation. Now I just need to write the code. What I'm trying to do, is when the browser loads a certain page, to insert text into a specific form. The form is as follows</p>
  
  <pre><code>&lt;div id="set_tags" class="advanced_option"&gt; 
     &lt;label for="post_tags" class="inline_input_label" id="post_tags_label"
         onclick="Element.remove($(this))" 
         style="left:8px; right:auto; text-align:left"&gt;tags&lt;/label&gt; 
     &lt;input id="post_tags" name="post[tags]" type="text"/&gt; 
   &lt;/div&gt; 
  </code></pre>
  
  <p>I haven't worked much with javascript, so is there a way to add the text "Music" to this when the page is loaded?</p>