Code
<Head>
<Script Language="JavaScript">
var computed = false
var decimal = 0
function convert (entryform, from, to)
{convertfrom = from.selectedIndex
convertto = to.selectedIndex
entryform.display.value = (entryform.input.value * from[convertfrom].value / to[convertto].value )}
function addChar (input, character)
{if((character=='.' && decimal=="0") || character!='.')
{(input.value == "" || input.value == "0") ? input.value = character : input.value += character
convert(input.form,input.form.measure1,input.form.measure2)
computed = true
if (character=='.')
{decimal=1}}}
function openVothcom()
{window.open("","Display window","toolbar=no,directories=no,menubar=no");}
function clear (form)
{form.input.value = 0
form.display.value = 0
decimal=0}
function changeBackground(hexNumber)
{document.bgColor=hexNumber}
</Script>
</Head>
<Body>
<Form Method="POST" Name="background">
<Input Type="button" Value="Желтый" OnClick="changeBackground('#fff000')">
<Input Type="button" Value="Чёрный" OnClick="changeBackground('#000000')">
<Input Type="button" Value="Белый" OnClick="changeBackground('#ffffff')">
<Input Type="button" Value="Зелёный" OnClick="changeBackground('#00ff00')">
<Input Type="button" Value="Синий" OnClick="changeBackground('#0000ff')">
<Input Type="button" Value="Оранжевый" OnClick="changeBackground('#ff8000')">
<Input Type="button" Value="Серый" OnClick="changeBackground('#c0c0c0')">
<Input Type="button" Value="Красный" OnClick="changeBackground('#ff0000')">
</Form>
</Body>
