how to ask bgcolor in js code example

Example 1: javascript style background color

// change background color for specific id ..
function changebackground(){
	document.getElementById('id').style.backgroundColor = 'green' ; 
}
// change background color for whole body..
function changebackground(){
	document.body.style.backgroundColor = 'green';
}

Example 2: javascript change background color

function changeBackground(color) {
   document.body.style.background = color;
}

window.addEventListener("load",function() { changeBackground('red') });