Force Links To New Windows

From GreaseSpot

Useful when you have altered the page in a custom way (i.e. via user input) and need to preserve the customized page without repainting form fields or customized nodes. This assumes only anchor links, not button or JavaScript induced links:

var anchorTags=document.links;
for (var i=anchorTags.length - 1; i >= 0; --i) {
  anchorTags[i].target = "_blank";
}