hiddenLayers = function(mylayers, imgObject) { 

    if(typeof(mylayers)=="object") { 

        for(var x=0; x<mylayers.length; x++) { 

            var obj = document.getElementById(mylayers[x]).style; 

            if(obj.display == "") obj.display = "block"; 

            obj.display = (obj.display == "block") ? "none" : "block";
            
            //imgSwitch
            
            if(obj.display == "block") {
            	imgObject.src = 'images/layout/minus.gif';
            } else {
            	imgObject.src = 'images/layout/plus.gif';
            }

        } 
    } 
};