String.prototype.endsWith = function(s) 
{
	return this.length >= s.length && this.substr(this.length - s.length) == s;
}

String.prototype.startsWith = function(s) 
{
	return this.length >= s.length && this.substr(0, s.length) == s;
}

function round(value,precision)
{
	var exp = Math.pow(10,precision);
	
	return Math.round(value*exp)/exp;
}

var unitRatios = new Array();

function addUnit(name,ratio)
{
	unitRatios[name] = ratio;
}

addUnit("Kilometer",1000);
addUnit("Meter",1);
addUnit("Centimeter",0.01);
addUnit("Millimeter",0.001);
addUnit("Micrometer",0.000001);
addUnit("Nanometer",0.000000001);
addUnit("Angstrem",0.0000000001);

addUnit("Mile",1609.344);
addUnit("Yard",0.9144);
addUnit("Foot",0.3048);
addUnit("Inch",0.0254);

addUnit("NauticalMile",1851.852);

addUnit("Parsec",648000/Math.PI*149597870700);
addUnit("LightYear",9460730472580800);
addUnit("AstronomicalUnit",149597870700);

addUnit("Sazen",1.787);
addUnit("Lokiec",0.59554);
addUnit("Stopa",0.29777);
addUnit("Sztych",0.19851);
addUnit("Cwierc",0.14887);
addUnit("Dlon",0.07444);
addUnit("Palec",0.02482);
addUnit("Ziarno",0.00310);

function initialize()
{
	document.chooseForm.unitMeter.value = 1;
	recalculate(document.chooseForm.unitMeter);
}

function recalculate(field)
{
	if(field.value.indexOf(',')>0)
		field.value = field.value.replace(',','.');

	var numberRegExp = new RegExp("^[0-9\.,-e\+]*$");		
	if(!numberRegExp.test(field.value))
		field.value = field.value.replace(/[^0-9\.,-e\+]*/ig,'');	
	
	//check for double decimal separator
	var firstSep = field.value.indexOf(".");
	var secondSep = firstSep>0?field.value.indexOf(".",firstSep+1):-1;
	if(firstSep>0 && secondSep>firstSep)
	{
		field.value = field.value.substring(0,secondSep);
	}
	
	if(field.value[field.value.length-1]=='.')
		return;
	
	var reset = false;
	if(field.value.length == 0)
	{
		reset = true;
	}
	
	var ratio = field.value * unitRatios[field.id.substring(4)];
		
   for(var i = 0; i < document.chooseForm.elements.length; i++)
   {
		var currentElement = document.chooseForm.elements[i];
		
		if(currentElement == field)
			continue;
		
		if(reset)
		{
			currentElement.value = '';
			continue;
		}
				
		
		var result = (ratio / unitRatios[currentElement.id.substring(4)]).toPrecision(7);
		if(result>0.0000001 && result<10000000)
			result = round(result,6);
		
		currentElement.value = result;
	}
}

function selectInput(field)
{
	addClass(field,"form-selected");
	
	for(var i = 0; i < document.chooseForm.elements.length; i++)
   {
		var currentElement = document.chooseForm.elements[i];
		
		if(currentElement == field)
			continue;
			
		removeClass(currentElement,"form-selected");
	}
}

function addClass(item, classname) 
{
    var obj = item
    if (typeof item=="string") {
        obj = document.getElementById(item)
    }
    obj.className += " " + classname
}

function removeClass(item, classname) 
{
    var obj = item
    if (typeof item=="string") {
        obj = document.getElementById(item)
    }
    var classes = ""+obj.className
    while (classes.indexOf(classname)>-1) {
        classes = classes.replace (classname, "")
    }
    obj.className = classes
}