function addLoadEvent(func) {
          var oldonload = window.onload;
          if (typeof window.onload != 'function') {
            window.onload = func;
          } else {
            window.onload = function() {
              oldonload();
              func();
            }
          }
        }

        function attachRolloverHandlers() {

            var nav = document.getElementById('nav') // get navigation list
           var clsLinks = nav.getElementsByTagName('a');
           
           for (var iCounter=0; iCounter<clsLinks.length; iCounter++)
           {
            //alert(clsLinks[iCounter].firstChild.id);
           if (clsLinks[iCounter].firstChild.id != '') {
           clsLinks[iCounter].onmouseover = function(){return changeImages( clsLinks[iCounter].firstChild.id ,  'on' );} // attach remember handler
           //clsLinks[iCounter].onmouseout = function(){return changeImages( clsLinks[iCounter].firstChild.id , 'off' );} // attach remember handler
           } 
           }
        }

        function changeImages(i, d) {
            var imageRoot = 'images/n/';
            var image = $(i);
           image.src = imageRoot+ i + '_' + d + '.gif';
           
           if(d == 'off') {
                  image.style.display = 'none';
                   Effect.Appear(i, { duration: 1.0, from:0.5, to:1.0});
           }
        }

        // initialise
        //addLoadEvent(attachRolloverHandlers);
        
        function checkForm() {
    		
			    var oForm = document.forms.login;
    			
			    if(!oForm.email.value.length || !oForm.password.value.length) {
    			
				    alert("Please supply both your email address and password to sign-in to Manchester Digital.");
				    return false;
    				
			    } else {
    			
				    return true;
			    }
		    }