Highlight links that open in a new window

This piece of CSS code will highlight links that open in a new window so that user knows before hand that link will pop open in a new tab or window.

a[target="_blank"]:before,
a[target="new"]:before {
 margin:0 5px 0 0;
 padding:1px;
 outline:1px solid #333;
 color:#333;
 background:#ff9;
 font:12px "Zapf Dingbats";
 content: "\279C";
}