var property = new Array();
var unit = new Array();
var factor = new Array();

property[0] = "Acceleration";
unit[0] = new Array("Meter/sekundkvadrat (m/s^2)", "Foot/sekundkvadrat (ft/s^2)", "Tyngdaccelerationen (g)", "Galileo (gal)", "Inch/sekundkvadrat (in/s^2)");
factor[0] = new Array(1, .3048, 9.806650, .01, 2.54E-02);

property[1] = "Area";
unit[1] = new Array("Kvadratmeter (m^2)", "Acre (acre)", "Are", "Barn (barn)", "Hektar", "Rood", "Kvadratcentimeter (cm^2)", "Kvadratkilometer (km^2)", "Circular mil", "Square foot (ft^2)", "Square inch (in^2)", "Square mile (mi^2)", "Square yard (yd^2)");
factor[1] = new Array(1, 4046.856, 100, 1E-28, 10000, 1011.71413184285, .0001, 1000000, 5.067075E-10, 9.290304E-02, 6.4516E-04, 2589988, .8361274);

property[2] = "Densitet";
unit[2] = new Array("Kilogram/kubikmeter", "Grain/galon", "Gram/kubikcentimeter", "Pound mass/cubic foot", "Pound mass/cubic-inch", "Ounces/gallon (UK,liq)", "Ounces/gallon (US,liq)", "Ounces (mass)/inch", "Pound mass/gal (UK,liq)", "Pound mass/gal (US,liq)", "Slug/cubic foot", "Tons (long,mass)/cub.yard");
factor[2] = new Array(1, .01711806, 1000, 16.01846, 27679.91, 6.236027, 7.489152, 1729.994, 99.77644, 119.8264, 515.379, 1328.939);

property[3] = "Effekt";
unit[3] = new Array("Watt (W)", "Kilowatt (kW)", "Megawatt (MW)", "Milliwatt (mW)", "Calorie (thermo)/second", "Calorie (thermo)/minute", "Erg/second", "Foot-pound force/hour", "Foot-pound force/minute", "Foot-pound force/second", "Horsepower(550 ft lbf/s)", "Horsepower (electric)", "Horsepower (boiler)", "Horsepower (metrisk)", "Horsepower (UK)", "Kilocalorie (thermo)/min", "Kilocalorie (thermo)/sec");
factor[3] = new Array(1, 1000, 1000000, .001, 4.184, 6.973333E-02, .0000001, .0003766161, .02259697, 1.355818, 745.7, 746, 9809.5, 735.499, 745.7, 69.7333, 4184);

property[4] = "Elektricitet";
unit[4] = new Array("Coulomb (Cb)", "Abcoulomb", "Amperetimme (A hr)", "Faraday (F)", "Statcoulomb", "Millifaraday (mF)", "Microfaraday (mu-F)", "Picofaraday (pF)");
factor[4] = new Array(1, 10, 3600, 96521.8999999997, .000000000333564, 96.5219, 9.65219E-02, 9.65219E-05);

property[5] = "Energi";
unit[5] = new Array("Joule (J)", "Kalori (cal)", "Elektronvolt (eV)", "Erg (erg)", "Foot-pound force", "Foot-poundal", "Horsepower-hour", "Kilokalori (kcal)", "Kilowatt-timmar (kWh)", "Volt-coulomb (V Cb)", "Watt timmar (Wh)", "Watt sekunder (Ws)");
factor[5] = new Array(1, 4.1868, 1.6021E-19, .0000001, 1.355818, 4.214011E-02, 2684077.3, 4186.8, 3600000, 1, 3600, 1);

property[6] = "Hastighet";
unit[6] = new Array("Meter/sekund (m/s)", "Foot/minute (ft/min)", "Foot/second (ft/sec)", "Kilometer/timmen (km/h)", "Knot (int'l)", "Mile (US)/hour (mph)", "Mile (nautical)/hour", "Mile (US)/minute", "Mile (US)/second", "Ljusets hastighet (c)", "Mach (STP)(a)");
factor[6] = new Array(1, 5.08E-03, .3048, .2777778, .5144444, .44707, .514444, 26.8224, 1609.344, 299792458, 340.0068750);

property[7] = "Kraft";
unit[7] = new Array("Newton (N)", "Dyne (dy)", "Kilogram (kg)", "Kilopond (kp)", "Kip (k)", "Ounce force (ozf)", "Pound-force (lbf)", "Poundal");
factor[7] = new Array(1, .00001, 9.806650, 9.806650, 4448.222, .2780139, 4.4482216, .138255);

property[8] = "Kraft / Längd";
unit[8] = new Array("Newtonmeter (Nm)", "Pound force/inch (lbf/in)", "Pound force/foot (lbf/ft)");
factor[8] = new Array(1, 175.1268, 14.5939);

property[9] = "Ljus";
unit[9] = new Array("Lumen/kvadratmeter (Lu/m^2)", "Lumen/kvadratcentimeter", "Lumen/sq.foot", "Foot-candle (ft-cdl)", "Foot-lambert", "Candela/kvadratmeter", "Candela/kvadratcentimeter", "Lux (lux)", "Phot");
factor[9] = new Array(1, 10000, 10.76391, 10.76391, 10.76391, 3.14159250538575, 31415.9250538576, 1, 10000);

property[10] = "Längd";
unit[10] = new Array("Meter (m)", "Ångström (Å)", "Astronomical unit (AU)", "Calibre (cal)", "Centimeter (cm)", "Kilometer (km)", "Ell", "Em", "Fathom", "Furlong", "Fermi (fm)", "Foot (ft)", "Inch (in)", "League (int'l)", "League (UK)", "Light year (LY)", "Mikrometer (µm)", "Mil", "Millimeter (mm)", "Nanometer (nm)", "Mile (int'l nautical)", "Mile (UK nautical)", "Mile (US nautical)", "Mile (US statute)", "Parsec", "Pica (printer)", "Picometer (pm)", "Point (pt)", "Rod", "Yard (yd)");
factor[10] = new Array(1, 1E-10, 1.49598E11, .000254, .01, 1000, 1.143, 4.2323E-03, 1.8288, 201.168, 1E-15, .3048, .0254, 5556, 5556, 9.46055E+15, .000001, 10000, .001, 1E-9, 1852, 1853.184, 1852, 1609.344, 3.08374E+16, 4.217518E-03, 1E-12, .0003514598, 5.0292, .9144);

property[11] = "Massa";
unit[11] = new Array("Kilogram (kgr)", "Gram (gr)", "Milligram (mgr)", "Microgram (µgr)", "Carat (ct)", "Hundredweight (long)", "Hundredweight (short)", "Pound mass (lbm)", "Pound mass (troy)", "Ounce mass (ozm)", "Ounce mass (troy)", "Slug", "Ton (assay)", "Ton (long)", "Ton (short)", "Ton (metrisk)", "Tonne");
factor[11] = new Array(1, .001, 1e-6, .000000001, .0002, 50.80235, 45.35924, .4535924, .3732417, .02834952, .03110348, 14.5939, .02916667, 1016.047, 907.1847, 1000, 1000);

// !!! Caution: Temperature requires an increment as well as a multiplying factor
// !!! and that's why it's handled differently
// !!! Be VERY careful in how you change this behavior
property[12] = "Temperatur";
unit[12] = new Array("Celsius ('C)", "Fahrenheit ('F)", "Kelvin ('K)", "Rankine ('R)");
factor[12] = new Array(1,  0.555555555555, 1, 0.555555555555);
tempIncrement = new Array(0, -32, -273.15, -491.67);

property[13] = "Tid";
unit[13] = new Array("Sekunder (s)", "Dagar (mean solar)", "Dagar (sidereal)", "Timmar (mean solar)", "Timmar (sidereal)", "Minuter (mean solar)", "Minuter (sidereal)", "Månader (mean calendar)", "Sekunder (sidereal)", "År (calendar)", "År (tropical)", "År (sidereal)");
factor[13] = new Array(1, 8.640E4, 86164.09, 3600, 3590.17, 60, 60, 2628000, .9972696, 31536000, 31556930, 31558150);

property[14] = "Tryck";
unit[14] = new Array("Newton/kvadratmeter", "Atmosfär (standard)", "Atmosfär (teknisk)", "Bar", "Centimeter kvicksilver(cmHg)", "Decibar", "Kgr force/sq.centimeter", "Kgr force/sq.meter", "Kip/square inch", "Millibar", "Millimeter kvicksilver(mmHg)", "Pascal (Pa)", "Kilopascal (kPa)", "Megapascal (Mpa)", "Poundal/sq.foot", "Pound-force/sq.foot", "Pound-force/sq.inch (psi)", "Torr (mmHg,0'C)");
factor[14] = new Array(1, 101325, 98066.5, 100000, 1333.22, 10000, 98066.5, 9.80665, 6894757, 100, 133.3224, 1, 1000, 1000000, 47.88026, 47.88026, 6894.757, 133.322);

property[15] = "Volym";
unit[15] = new Array("Cubic Meter (m^3)", "Cubic centimeter", "Cubic millimeter", "Acre-foot", "Barrel (oil)", "Board foot", "Bushel (US)", "Cup", "Fluid ounce (US)", "Cubic foot", "Gallon (UK)", "Gallon (US,dry)", "Gallon (US,liq)", "Gill (UK)", "Gill (US)", "Cubic inch (in^3)", "Liter (new)", "Liter (old)", "Ounce (UK,fluid)", "Ounce (US,fluid)", "Peck (US)", "Pint (US,dry)", "Pint (US,liq)", "Quart (US,dry)", "Quart (US,liq)", "Stere", "Tablespoon", "Teaspoon", "Ton (register)", "Cubic yard");
factor[15] = new Array(1, .000001, .000000001, 1233.482, .1589873, .002359737, .03523907, .0002365882, .00002957353, .02831685, .004546087, .004404884, .003785412, .0001420652, .0001182941, .00001638706, .001, .001000028, .00002841305, .00002957353, 8.8097680E-03, .0005506105, 4.7317650E-04, .001101221, 9.46353E-04, 1, .00001478676, .000004928922, 2.831685, .7645549);



// *** Functions *************************************************************

function UpdateUnitMenu(propMenu, unitMenu){
	// Updates the units displayed in the unitMenu according to the selection of
	// property in the propMenu.
	var i;

	i = propMenu.selectedIndex;
	FillMenuWithArray(unitMenu, unit[i]);
}

function FillMenuWithArray(myMenu, myArray){
	// Fills the options of myMenu with the elements of myArray.
	// !CAUTION!: It replaces the elements, so old ones will be deleted.
	var i;

	myMenu.length = myArray.length;
	for(i = 0; i < myArray.length; i++){
		myMenu.options[i].text = myArray[i];
	}
}

function CalculateUnit(sourceForm, targetForm){
	// A simple wrapper function to validate input before making the conversion
	var sourceValue = sourceForm.unit_input.value;

	// First check if the user has given numbers or anything that can be made to
	// one...
	sourceValue = parseFloat(sourceValue);
	if ( !isNaN(sourceValue) || sourceValue == 0){
		// If we can make a valid floating-point number, put it in the
		// text box and convert!
		sourceForm.unit_input.value = sourceValue;
		ConvertFromTo(sourceForm, targetForm);
		} else {
		alert("What you gave me cannot be converted or is zero!");
	}
}

function ConvertFromTo(sourceForm, targetForm){
	// Converts the contents of the sourceForm input box to the units specified in
	// the targetForm unit menu and puts the result in the targetForm input box.
	// In other words, this is the heart of the whole script...
	var propIndex;
	var sourceIndex;
	var sourceFactor;
	var targetIndex;
	var targetFactor;
	var result;

	// Start by checking which property we are working in...
	propIndex = document.property_form.the_menu.selectedIndex;

	// Let's determine what unit are we converting FROM (i.e. source) and the
	// factor needed to convert that unit to the base unit.
	sourceIndex = sourceForm.unit_menu.selectedIndex;
	sourceFactor = factor[propIndex][sourceIndex];

	// Cool! Let's do the same thing for the target unit --the units we are
	// converting TO:
	targetIndex = targetForm.unit_menu.selectedIndex;
	targetFactor = factor[propIndex][targetIndex];

	// Simple, huh? let's do the math: a) convert the source TO the base unit:
	// (The input has been checked by the CalculateUnit function).
	result = sourceForm.unit_input.value;
	// Handle Temperature increments!
	if (property[propIndex] == "Temperature"){
		result = parseFloat(result) + tempIncrement[sourceIndex];
	}
	result = result * sourceFactor;

	// not done yet... now, b) use the targetFactor to convert FROM the base unit
	// to the target unit...
	result = result / targetFactor;
	// Again, handle Temperature increments!
	if (property[propIndex] == "Temperature"){
		result = parseFloat(result) - tempIncrement[targetIndex];
	}

	// Ta-da! All that's left is to update the target input box:
	targetForm.unit_input.value = result;
}

function ClearForm(){
	// Clears the input boxes...
	document.form_A.unit_input.value = "";
	document.form_B.unit_input.value = "";
}