控制背景颜色变化

<script language="JavaScript">
var red = 0;

var green = 0;

var blue = 0;

var value = 0;

var convert = new Array()

var hexbase = new Array("0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F");

for (x = 0; x < 16; x++) {

    for (y = 0; y < 16; y++) {

        convert[value] = hexbase[x] + hexbase[y];

        value++;

    }

}

function clear() {

    document.color.bl.value = blue;

    document.color.rd.value = red;

    document.color.gr.value = green;

}

function display() {

    redx = convert[red]

    greenx = convert[green]

    bluex = convert[blue]

    var rgb = "#" + redx + greenx + bluex;

    document.color.rgbdspl.value = rgb;

    document.bgColor = rgb;

}

function upred(x) {

    if ((red + x) <= 255)

    red += x

    document.color.rd.value = red;

    display()

}

function downred(x) {

    if ((red - x) >= 0)

    red -= x

    document.color.rd.value = red;

    display()

}

function upgreen(x) {

    if ((green + x) <= 255)

    green += x

    document.color.gr.value = green;

    display()

}

function downgreen(x) {

    if ((green - x) >= 0)

    green -= x

    document.color.gr.value = green;

    display()

}

function upblue(x) {

    if ((blue + x) <= 255)

    blue += x

    document.color.bl.value = blue;

    display()

}

function downblue(x) {

    if ((blue - x) >= 0)

    blue -= x

    document.color.bl.value = blue;

    display()

}
</script>

<form name="color">
	<table align="center">
	<tr align="Center">
		<td width="52">
			<input name="red" type="button" value=" +50 " onclick="upred(50)">
		</td>
		<td width="58">
			<input name="red2" type="button" value=" + 10 " onclick="upred(10)">
		</td>
		<td width="46">
			<input name="red2" type="button" value=" + 1" onclick="upred(1)">
		</td>
		<td width="52">
			<font color="#FF0000" size='+3'><b><font color="#FA0000" face="楷体_GB2312">红</font></b></font>
		</td>
		<td width="46">
			<input name="red-" type="button" value=" - 1" onclick="downred(1)">
		</td>
		<td width="58">
			<input name="red-" type="button" value=" - 10 " onclick="downred(10)">
		</td>
		<td width="52">
			<input name="red-" type="button" value=" -50 " onclick="downred(50)">
		</td>
		<td width="29">
			<input type="text" name="rd" size='3'>
		</td>
	</tr>
	<tr align="Center">
		</table>
		<td width="52">
			<input name="green" type="button" value=" +50 " onclick="upgreen(50)">
		</td>
		<td width="58">
			<input name="green" type="button" value=" + 10 " onclick="upgreen(10)">
		</td>
		<td width="46">
			<input name="green" type="button" value=" + 1" onclick="upgreen(1)">
		</td>
		<td width="52">
			<font color="#00FF00" size='+3'><b><font color="#00FA00" face="楷体_GB2312">绿</font></b></font>
		</td>
		<td width="46">
			<input name="green-" type="button" value=" - 1" onclick="downgreen(1)">
		</td>
		<td width="58">
			<input name="green-" type="button" value=" - 10 " onclick="downgreen(10)">
		</td>
		<td width="52">
			<input name="green-" type="button" value=" -50 " onclick="downgreen(50)">
		</td>
		<td width="29">
			<input type="text" name="gr" size='3'>
		</td>
	</tr>
	</table>
</form>