Cacher is the code snippet organizer for pro developers

// Most common 
<script type="text/javascript">
   if (top != self) top.location.replace(location);
</script>

// Modern Framekiller
// http://seclab.stanford.edu/websec/framebusting/framebust.pdf
<style> html{display:none;} </style>
<script>
   if (self == top) {
       document.documentElement.style.display = 'block'; 
   } else {
       top.location = self.location; 
   }
</script>