//names of the various academic and subject areas of the site.
var academic_urls = new Array('Foyer', 'Library', 'Theater', 'Annex');

//base IDs of the highlight images for the academic/subject areas.
var academic_ids = {
	Foyer: 'nav_foyer',
	Library: 'nav_library',
	Theater: 'nav_theater',
	Annex: 'nav_annex'
};

// custom image rollover function
// grabs an image by id, changes the source of the image.
function rollover(imageId) {
    if (document.getElementById) {
        var image = document.getElementById(imageId);
        var src = image.src;
        if(src.match('-nr')) {
            src = src.replace('-nr', '-ro');
        } else {
            src = src.replace('-ro', '-nr');
        }
        image.src = src;
    }
    return false;
}

//pass image IDs to this function. It will find the source of the image, munge
//it into the url for the rollover image, and then preload it.
function preload_images() {
    if (document.getElementById) {        
        var d = document;
        var image_count = academic_urls.length;
        var url;
        d.ise_images = new Array(image_count);

        for (var i = 0; i < academic_urls.length; i++) { 
            var image = d.getElementById(academic_ids[academic_urls[i]]);
            var src = image.src;
            if(src.match('-nr')) {
                src = src.replace('-nr', '-ro');
                d.ise_images[i] = new Image();
                d.ise_images[i].src = src;
            }
        }
    }
}

function highlight_academic_bar () {
    if(document.getElementById) {
        var d = document;
        var doc_url = document.URL;

        for (var i = 0; i < academic_urls.length; i++) {
            var url = academic_urls[i];
             if(doc_url.match(url)) {
                var image = d.getElementById(academic_ids[url]);
                var src = image.src;
                if(src.match('-nd')) {
                    src = src.replace('-nd', '-dn');
                }
                image.src = src;                
             }            
        }
    }
}