var SideBar = function() {
    
    this.aElementIds = [];
    this.oElements = {};
    this.oContentsElement = {};
    
    this.init = function() {
        for (var i=0; i<this.aElementIds.length; i++) {
            this.oElements[this.aElementIds[i]] = document.getElementById(this.aElementIds[i]);
            this.oContentsElement[this.aElementIds[i]] = document.getElementById(this.aElementIds[i] + "_content");
        }
        
        this.expandSection(this.aElementIds[0]);
    }
    
    this.collapseAllSections = function() {
        for (var i=0; i<this.aElementIds.length; i++) {
            this.oElements[this.aElementIds[i]].className = "collapsed";
            this.oContentsElement[this.aElementIds[i]].style.display = "none";
        }
    }
    
    this.expandSection = function(id) {
        this.collapseAllSections();

        var section = this.oElements[id];
        var content = this.oContentsElement[id];

        section.className = "expanded";
        content.style.display = "block";
    }
}