title: What does a[href^="..."] do in CSS?
body: <p>I have used CSS before and I came across the below CSS style, don't have a clue what it does. </p>
  
  <pre class="lang-css prettyprint-override"><code>a[href^="http:"] {
     background: url(img/keys.gif) no-repeat right top;
  }
  a[href^="http://mysite.com"], a[href^="http://www.mysite.com"] {
     background-image: none; padding-right:0;
  }
  </code></pre>