title: what is base64,iVBORw0K.... on css?
body: <p>I am very new learner. I am learning php, mysql and css. I am reading many source code to understand how the real programer work. On a site i saw a source code where some one wrote the following line on the css..</p>
  
  <pre><code>background:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAxCAIAAACUDVRzAAAAA3NCSVQICAjb4U/gAAAALElEQVQImWMwMrJi+v//PxMDw3+m//8ZoPR/qBgDEhuXGLoeYswhXg8R5gAAdVpfoJ3dB5oAAAAASUVORK5CYII=) 100% 100%;
  </code></pre>
  
  <p>Now i am not understanding what is base64 and what is the rest of non readable code?
  You can find the whole source code of style.css here
  <a href="http://blogaddition.com/2013/01/database-driven-multi-level-horizontal-css-menu-with-php-and-mysql/" rel="nofollow">http://blogaddition.com/2013/01/database-driven-multi-level-horizontal-css-menu-with-php-and-mysql/</a></p>
  
  <p>please help me to learn and understand. </p>