title: How to create an triangle shape (fixed height, width=100%) with background
body: <p>I have a graphic background, and I need to display a colored triangle in the top left corner (independing the resolution). </p>
  
  <p>Can I create a triangle shaped element using only HTML/CSS/JS with width = 100% and height = 200px with background = red?</p>
  
  <p>I can create it by IMG with width=100%, but I was hoping for a better solution than resizing an image.</p>
  
  <p>The solution needs to be compatible with IE7+ and using browser's versions (more than 2%).</p>
  
  <p>Thanks</p>