/* Scan all links in the document and set classes on them if 
 * they point outside the site, or are special protocols
 * To disable this effect for links on a one-by-one-basis,
 * give them a class of 'link-plain'
 */
function scanforlinks(){

    // terminate if we hit a non-compliant DOM implementation

    contentarea = document.getElementById('mainColumn');
    if (! contentarea){return false}
    links = contentarea.getElementsByTagName('a');
    for (i=0; i < links.length; i++){      
        if ((links[i].getAttribute('href'))&&(links[i].className.indexOf('link-plain')==-1 )){
            var linkval = links[i].getAttribute('href')
            // check if the link href is a relative link, or an absolute link to the current host.
            if (linkval.toLowerCase().indexOf(window.location.protocol+'//'+window.location.host)==0) {
                // absolute link internal to our host - do nothing
            } else if (linkval.indexOf('http:') != 0){
                // not a http-link. Possibly an internal relative link, but also possibly a mailto or other protocol
                // add tests for relevant protocols as you like.
                protocols = ['mailto', 'ftp', 'news', 'irc', 'h323', 'sip', 'callto', 'https', 'feed', 'webcal']
                // h323, sip and callto are internet telephony VoIP protocols
                for (p=0; p < protocols.length; p++){
                    if (linkval.indexOf(protocols[p]+':') == 0){
                    // if the link matches one of the listed protocols, add className = link-protocol
//                       wrapNode(links[i], 'span', 'link-'+protocols[p])
                        break;
                    }
                }
            }else{
                // we are in here if the link points to somewhere else than our site.
                if ( links[i].getElementsByTagName('img').length == 0 ){
                    // we do not want to mess with those links that already have images in them
//                    wrapNode(links[i], 'span', 'link-external');
                    links[i].setAttribute('target', '_blank');
                }  
            }
        }
    }
}