var agt=navigator.userAgent.toLowerCase();
var is_major = parseInt(navigator.appVersion);
var is_minor = parseFloat(navigator.appVersion);
var is_ie     = ((agt.indexOf("msie") != -1) && (agt.indexOf("opera") == -1));
var is_ie3    = (is_ie && (is_major < 4));
var is_ie4    = (is_ie && (is_major == 4) && (agt.indexOf("msie 4")!=-1) );
var is_ie4up  = (is_ie && (is_major >= 4));
var is_ie5    = (is_ie && (is_major == 4) && (agt.indexOf("msie 5.0")!=-1) );
var is_ie5_5  = (is_ie && (is_major == 4) && (agt.indexOf("msie 5.5") !=-1));
var is_ie5up  = (is_ie && !is_ie3 && !is_ie4);
var is_ie5_5up =(is_ie && !is_ie3 && !is_ie4 && !is_ie5);
var is_ie6    = (is_ie && (is_major == 4) && (agt.indexOf("msie 6.")!=-1) );
var is_ie6up  = (is_ie && !is_ie3 && !is_ie4 && !is_ie5 && !is_ie5_5);
var is_winxp = ((agt.indexOf("windows nt 5.1")!=-1));
var reNumeric = /^\d+$/
var reEmail = /^.+@.+\..+$/

layerHeight = 95;
subMenuSpace = 20;
if (is_ie5 || is_ie5_5) {
	spanWidth = "190";
	subMenuSpace = 20;
}
else if (is_ie6 || is_ie6up) {
	if (is_winxp) {
		spanWidth = "205";
		subMenuSpace = 20;
	}
	else {
		spanWidth = "205";
		subMenuSpace = 20;
	}
}
else {
	spanWidth = "205";
	subMenuSpace = 20;
}

function english() {
 url=window.location.href;
 urlString = url.split("chi/");
 toUrl = "../eng/"+urlString[urlString.length-1];
 window.location.href=toUrl;
 return false;
 }

function isEmpty(s)
{   return ((s == null) || (s.length == 0))
}

function isLetter (c)
{   return ( ((c >= "a") && (c <= "z")) || ((c >= "A") && (c <= "Z")) )
}

function isDigit(c) {
    return ((c >= "0") && (c <= "9"));
}

function isAlphabetic (s)

{   var i;

    if (isEmpty(s)) 
       if (isAlphabetic.arguments.length == 1) return defaultEmptyOK;
       else return (isAlphabetic.arguments[1] == true);

    for (i = 0; i < s.length; i++)
    {   
        var c = s.charAt(i);

        if (!isLetter(c))
        return false;
    }

    return true;
}

function showLayer(name) {
	if (is_ie5 || is_ie5_5 || is_ie6 || is_ie6up) {
		layer = eval("document.all." + name);

			left1 = 145;
			imgWidth = 77;
			spanWidth = 205;
			if (name == "about") {
				layerLeft = 145;
			}
			else if (name == "hot") {
				layerLeft = left1 + imgWidth;
			}
			else if (name == "residential") {
				layerLeft = left1 + imgWidth * 2;
			}
			else if (name == "residential1") {
				layerLeft = left1 + imgWidth * 2 + spanWidth;
			}
			else if (name == "residential2") {
				layerLeft = left1 + imgWidth * 2 + spanWidth;
			}
			else if (name == "residential3") {
				layerLeft = left1 + imgWidth * 2 + spanWidth;
			}
			else if (name == "business") {
				layerLeft = left1 + imgWidth * 3;
			}
			else if (name == "business1") {
				layerLeft = left1 + imgWidth * 3 + spanWidth;
			}
			else if (name == "business2") {
				layerLeft = left1 + imgWidth * 3 + spanWidth;
			}
			else if (name == "business3") {
				layerLeft = left1 + imgWidth * 3 + spanWidth;
			}
			else if (name == "business4") {
				layerLeft = left1 + imgWidth * 3 + spanWidth;
			}
			else if (name == "business5") {
				layerLeft = left1 + imgWidth * 3 + spanWidth;
			}
			else if (name == "business6") {
				layerLeft = left1 + imgWidth * 3 + spanWidth;
			}
			else if (name == "local") {
				layerLeft = left1 + imgWidth * 4;
			}
			else if (name == "customer") {
				layerLeft = left1 + imgWidth * 5;
			}
			else if (name == "customer1") {
				layerLeft = left1 + imgWidth * 5 + spanWidth;
			}
			else if (name == "customer2") {
				layerLeft = left1 + imgWidth * 5 + spanWidth;
			}

		if (!isAlphabetic(name) && (layerLeft + 205) > document.body.clientWidth) {
			parentLayer = eval("document.all." + name.substring(0, name.length-1));
			layerLeft = parseInt(parentLayer.style.left) - 205;
			if (layerLeft < 0) {
				layerLeft = 0;
			}
		}
		else if (isAlphabetic(name) && (layerLeft + 205) > document.body.clientWidth) {
			layerLeft = document.body.clientWidth - 205;
		}
		layer.style.left = layerLeft;
		layer.style.visibility = "visible";
	}
}

function hideLayer(name) {
	if (is_ie5 || is_ie5_5 || is_ie6 || is_ie6up) {
		layer = eval("document.all." + name);
		layer.style.visibility = "hidden";
	}
}

function changeImage(name) {
	img = eval("document." + name);
	img.src = "images/" + name + ".gif";
}

function changeImageOver(name) {
	img = eval("document." + name);
	img.src = "images/" + name + "_over.gif";
}

function checkEmpty(field, name) {
	if (isEmpty(field.value)) {
		alert("請輸入" + name);
		field.select();
		field.focus();
		return false;
	}
	return true;
}

function checkDigitKeyPress() {
	if (window.event && (window.event.keyCode >= 48) && (window.event.keyCode <= 57)) {
		return true;
	}
	return false;
}

function checkNumeric(field, name) {
	if (!reNumeric.test(field.value)) {
		alert(name + '只接納數目字');
		field.select();
		field.focus();
		return false;
	}
	return true;
}

function checkEmail(field, name) {
	if (!reEmail.test(field.value)) {
		alert('請輸入正確的' + name);
		field.select();
		field.focus();
		return false;
	}
	return true;
}