function openWindow() {
    window.open(this.href,"_blank","width=600,height=400,top=15,left=15,resizable=1,menubar=1,toolbar=1,location=1,scrollbars=1"); 
    return false;
}

window.onload = function() {
    if (document.getElementsByTagName) {
       var allLinks = document.getElementsByTagName('a');
       for (var i=0, totalLinks = allLinks.length; i<totalLinks; i++) {
           if (allLinks[i].className.match(/nWin/)) {
              allLinks[i].onclick = openWindow;
              allLinks[i].setAttribute('title','This link to an external website opens in a new browser window');
           }
       }    
    }
}