function highlight_button(evt) {
    var textContainer = dojo.html.getParentByType(evt.currentTarget, "div");
    var btnType = textContainer.getAttribute("btnType");
    var btnID = textContainer.getAttribute("btnID");        
    
    var leftImg = dojo.byId(btnID + "_leftImg");    
    var rightImg = dojo.byId(btnID + "_rightImg");
        
    leftImg.src = "images/" + btnType + "_left_hl.png";
    textContainer.style.backgroundImage = "url(images/" + btnType + "_bg_hl.png)";    
    rightImg.src = "images/" + btnType + "_right_hl.png";
}

function unhighlight_button(evt) {
    var textContainer = dojo.html.getParentByType(evt.currentTarget, "div");
    var btnType = textContainer.getAttribute("btnType");    
    var btnID = textContainer.getAttribute("btnID");        
    
    var leftImg = dojo.byId(btnID + "_leftImg");    
    var rightImg = dojo.byId(btnID + "_rightImg");
        
    leftImg.src = "images/" + btnType + "_left.png";            
    textContainer.style.backgroundImage = "url(images/" + btnType + "_bg.png)";    
    rightImg.src = "images/" + btnType + "_right.png";
}