function popUp(URL, scrlbr, larghezza, altezza, sinistra, sopra) {
day = new Date();
id = day.getTime();
eval("page" + id + " = window.open(URL, '" + id + "', 'toolbar=0,scrollbars=" + scrlbr + ",location=0,statusbar=0,menubar=0,resizable=0,width=" + larghezza + ",height=" + altezza + ",left = " + sinistra + ",top =" + sopra + "');");
}

function overlay() {
	el = document.getElementById("overlay");
	el.style.visibility = (el.style.visibility == "visible") ? "hidden" : "visible";
}

function ShowHide(id)
	{
	var element = document.getElementById(id);
	
	if (element.style.display == '') 
		{
		element.style.display = 'none';
		}
	else
		{
		element.style.display = '';
		}

	}
function ShowHideMany(id1, id2, id3, id4, id5)/* ADD ONE ID HERE */
	{
	var element1 = document.getElementById(id1);
	var element2 = document.getElementById(id2);
	var element3 = document.getElementById(id3);
	var element4 = document.getElementById(id4);
	var element5 = document.getElementById(id5); /* ADD ONE ID HERE */
	
	if (element1.style.display == '') 
		{
		element1.style.display = 'none';
		}
	else
		{
		element1.style.display = '';
		}
	element2.style.display = 'none';
	element3.style.display = 'none';
	element4.style.display = 'none';
	element5.style.display = 'none';/* ADD ONE ELEMENT HERE */
	}


// OPACITA' E MOSTRA-NASCONDI FORM
function mkOpaque(id) {
	var el = document.getElementById(id);
	el.style.filter="alpha(opacity:50)";
	el.style.KHTMLOpacity="0.50";
	el.style.MozOpacity="0.50";
	el.style.opacity="0.50";
	}
 function removeOpacity(id) {
 	var el = document.getElementById(id);
	el.style.filter="alpha(opacity:100)";
	el.style.KHTMLOpacity="1";
	el.style.MozOpacity="1";
	el.style.opacity="1"; 
	}
	
 function startForm (){
	mkOpaque('content');
	ShowHide('form');
	document.getElementById('nome').focus();
	}
 function closeForm (){	
 	removeOpacity('content');
	ShowHide('form');
	}

 function checkMail()
	{

	var x = document.forms[0].sender.value;
	var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if (filter.test(x)) document.forms[0].submit()
	else alert('煩請填寫完整資料'); 
	}

<!-- TO MAKE A SLIDE EFFECT WHEN AN ANCHOR IS CLICKED -->

var timerlen = 5;
var slideAniLen = 250;

var timerID = new Array();
var startTime = new Array();
var obj = new Array();
var endHeight = new Array();
var moving = new Array();
var dir = new Array();

function slidedown(objname){
        if(moving[objname])
                return;

        if(document.getElementById(objname).style.display != "none")
                return; // cannot slide down something that is already visible

        moving[objname] = true;
        dir[objname] = "down";
        startslide(objname);
}

function slideup(objname){
        if(moving[objname])
                return;

        if(document.getElementById(objname).style.display == "none")
                return; // cannot slide up something that is already hidden

        moving[objname] = true;
        dir[objname] = "up";
        startslide(objname);
}

function startslide(objname){
        obj[objname] = document.getElementById(objname);

        endHeight[objname] = parseInt(obj[objname].style.height);
        startTime[objname] = (new Date()).getTime();

        if(dir[objname] == "down"){
                obj[objname].style.height = "1px";
        }

        obj[objname].style.display = "block";

        timerID[objname] = setInterval('slidetick(\'' + objname + '\');',timerlen);
}

function slidetick(objname){
        var elapsed = (new Date()).getTime() - startTime[objname];

        if (elapsed > slideAniLen)
                endSlide(objname)
        else {
                var d =Math.round(elapsed / slideAniLen * endHeight[objname]);
                if(dir[objname] == "up")
                        d = endHeight[objname] - d;

                obj[objname].style.height = d + "px";
        }

        return;
}

function endSlide(objname){
        clearInterval(timerID[objname]);

        if(dir[objname] == "up")
                obj[objname].style.display = "none";

        obj[objname].style.height = endHeight[objname] + "px";

        delete(moving[objname]);
        delete(timerID[objname]);
        delete(startTime[objname]);
        delete(endHeight[objname]);
        delete(obj[objname]);
        delete(dir[objname]);

        return;
}

function toggleSlide(objname){
  if(document.getElementById(objname).style.display == "none"){
    // div is hidden, so let's slide down
    slidedown(objname);
  }else{
    // div is not hidden, so slide up
    slideup(objname);
  }
}