var tevalue_c = document.getElementById("tevalue").innerHTML;
var teunit = "C";
var wgvalue_kmh = document.getElementById("wgvalue").innerHTML;
var wgunit = "km/h";


if (document.cookie) {
	var items = document.cookie.split ("; ");
	var i = 0;
	for (i=0;i<items.length;i++) {
		var values = items[i].split("=");
		if (values[0] == "teunit") {
			setTEUnit (values[1]);
	
		}
		if (values[0] == "wgunit") {
			setWGUnit (values[1]);
		}
	}

}


function setTEUnit (unit) {
	var value = 0;
	switch (unit) {
		case "C":
		teunit = unit;
		value = tevalue_c;
		showTEValueUnit (value, teunit);

		break;
		case "K":
		teunit = unit;
		value = eval(tevalue_c*1 + 273.15);
		showTEValueUnit (value, teunit);
	
		break;
		case "F":
		teunit = unit;
		value = eval(tevalue_c * 9 / 5 + 32);
		showTEValueUnit (value, teunit);

		break;

	}
}


function setWGUnit (unit) {
	var value = 0;
	switch (unit) {
		case "km/h":
		wgunit = unit;
		value = wgvalue_kmh;
		showWGValueUnit (value, wgunit);

		break;
		case "m/s":
		wgunit = unit;
		value = eval(wgvalue_kmh / 3.6);
		showWGValueUnit (value, wgunit);
	
		break;
		case "Kn":
		wgunit = unit;
		value = eval(wgvalue_kmh / 1.852);
		showWGValueUnit (value, wgunit);
	
		break;
		case "Bf":
		wgunit = unit;
		value = eval(Math.pow(wgvalue_kmh / 3.01, 2.0 / 3.0));
		showWGValueUnit (value, wgunit);
	
		break;


	}
}


function changeTEUnit () {
	switch (teunit) {
		case "C":
		setTEUnit("K");
		break;
		case "K":
		setTEUnit ("F");
		break;
		case "F":
		setTEUnit ("C");
	}
	setYearCookie ("teunit", teunit);
	
}


function changeWGUnit () {
	switch (wgunit) {
		case "km/h":
		setWGUnit("m/s");
		break;
		case "m/s":
		setWGUnit ("Kn");
		break;
		case "Kn":
		setWGUnit ("Bf");
		break;
		case "Bf":
		setWGUnit ("km/h");
		break;
	}
	setYearCookie ("wgunit", wgunit);
	
}


function showTEValueUnit (value, unit) {
	var rvalue = eval(Math.round(value * 100) / 100);
	document.getElementById("teunit").innerHTML = unit;
	document.getElementById("tevalue").innerHTML = rvalue;
}


function showWGValueUnit (value, unit) {
	var rvalue = eval(Math.round(value * 100) / 100);
	document.getElementById("wgunit").innerHTML = unit;
	document.getElementById("wgvalue").innerHTML = rvalue;
}


function setYearCookie (name, value) {
	var curDate = new Date ();
	curDate.setFullYear (curDate.getFullYear() + 1);
	document.cookie = name + "=" + value + "; expires=" + curDate.toGMTString() + ";";
}