// JavaScript Document

// config
var config = {
    container_id : 'globalnav',
    postfix : '_on'
};

window.onload = function() {
    rollOverImages();
}

function rollOverImages() {
    var container = document.getElementById(config.container_id);
    var nodes = container.getElementsByTagName('img');
    var images = [];
    
    for ( var i = 0; i < nodes.length; i++) {
        nodes[i].src_org = nodes[i].src;
        nodes[i].src_on  = nodes[i].src.replace(/(\.gif|\.jpg|\.png)/, config.postfix + "$1");
        preLoadImages(nodes[i].src_on);
        var check = nodes[i].src.match(/^.+(_on).+$/);
        if(check == null) {
            nodes[i].onmouseover = function() {
                this.src = this.src_on;
            }
            nodes[i].onmouseout = function() {
                this.src = this.src_org;
            }
        }
    }

    // preload
    function preLoadImages(url) {
        var i = images.length;
        images[i] = new Image();
        images[i].src = url;
    }
}