Javascript Example
Screen shot
Change Background Color of the webpage
<html>
<head>
<title>Change Back Ground Color of the Webpage</title>
<script language=\"javascript\" type=\"text/javascript\">
function change_color(value)
{

if(document.getElementById(\"red\").value==value)
{
document.bgColor=\"red\";
document.getElementById(\"green\").checked=false;
document.getElementById(\"blue\").checked=false;
}

if(document.getElementById(\"green\").value==value)
{
document.bgColor=\"green\";
document.getElementById(\"red\").checked=false;
document.getElementById(\"blue\").checked=false;
}

if(document.getElementById(\"blue\").value==value)
{
document.bgColor=\"blue\";
document.getElementById(\"red\").checked=false;
document.getElementById(\"green\").checked=false;
}

}
</script>
</head>
<body>
<h3>Click on Checkbox to change color of the webpage</h3>
<input id=\"red\" value=\"red\" type=\"checkbox\" onClick=\"change_color(this.value);\"/>Red <br>
<input id=\"green\" value=\"green\" type=\"checkbox\" onClick=\"change_color(this.value);\"/>Green <br>
<input id=\"blue\" value=\"blue\" type=\"checkbox\" onClick=\"change_color(this.value);\"/>Blue <br>
</body>
</html>

You can download source code here