Buttons Controlling Color of Box: Using form elements to control DOM with D3

<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
  font: 12px sans-serif;
  background-color: teal;
}

.buttons-div
{
  margin: 0 auto;
  width: 140px;
  height: 140px;
  position: absolute;
}

</style>
<body>

<h1>Buttons with Colors2</h1>
<p>Using form elements to control DOM and Very Simple Chart with D3.</p>

<div class='container' >
	<div class="buttons-div">
	  <h2>Select Variables</h2>
	</div>
	<div id="chart1"></div>
</div>

drawRadioButtons();
drawChart();

function drawChart(){
	console.log('draw chart!!');
	var margin = {top: 40, right: 40, bottom: 100, left: 180},
    // width = parseInt(d3.select('#chart').style('width'), 10);
    // width = width - margin.left - margin.right;
    // height = parseInt(d3.select('#chart').style('height'), 10);
    // height = height - margin.top - margin.bottom;
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

var targ = d3.select("#chart1");

var svg = targ.append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
    .append("g")
    .attr("transform", "translate(" + width/2 + "," +height/2 + ")");

svg.append('rect')
    	.attr('id', 'box')
    	.attr('x', 0)
    	.attr('y', 0)
    	.attr('width', 100)
    	.attr('height', 100)
    	.style('fill', 'grey')
}

function drawRadioButtons(){
	var targ = d3.select(".buttons-div");

var grp1 = {'name': 'Background Colors', 'buttons': [
					{'value':'teal', 'label':'Teal', 'checked':true},
					{'value':'DarkSeaGreen', 'label':'Light Green', 'checked':false},
					{'value':'#dbb5dd', 'label':'Pink', 'checked':false},
					{'value':'LightSteelBlue', 'label':'LightSteelBlue', 'checked':false} ]}
												
	targ.append('div')
		.append('p')
		.text(function(){return grp1['name']; });

for(button in grp1['buttons']){
		var b = grp1['buttons'][button];
		console.log(b['label'])
		drawRadioButton(targ, grp1['name'], b['label'], b['value'], b['checked'])
	}

var grp2 = {'name': 'Box Colors', 'buttons': [
					{'value':'teal', 'label':'teal', 'checked':false},
					{'value':'#a02b42', 'label':'red', 'checked':false},
					{'value':'#3a4e87', 'label':'blue', 'checked':false},
					{'value':'grey', 'label':'grey', 'checked':true},
					{'value':'green', 'label':'green', 'checked':false} ]}
												
	targ.append('div')
		.append('p')
		.text(function(){return grp2['name']; });

for(button in grp2['buttons']){
		var b = grp2['buttons'][button];
		console.log(b['label'])
		drawRadioButton(targ, grp2['name'], b['label'], b['value'], b['checked'])
	}

}

//-------------------------------------------------------------------------------------

// event listeners and actions
var inputElems = d3.selectAll("input");

inputElems.on("change", changeColor);

function changeColor(){

console.log(this.name)

if(this.name == "Background Colors"){
	  	d3.select('body').style('background-color', this.value)
	}

if(this.name == "Box Colors"){
	  	d3.select('#box').style('fill', this.value)
	}
}

//-------------------------------------------------------------------------------------

//ToDo: move font sizing to external css, and give this a group-class for styling!!
function drawRadioButton(targ_div, grp_name, label_txt, value, checked, fontsize){
	if(checked === undefined) { checked = false; }
	if(fontsize===undefined){ fontsize = '10px'}

var button = targ_div.append('div')
		
	button.append('label')
			.text(function(d){ return label_txt; })
			.style('font-size', fontsize)
		
	var radio = button.append('input')
		.attr('type', 'radio')
		.attr('name', grp_name)
		.attr('value', value)
		.style('float', 'left')
		.style('vertical-align', 'bottom')
		
	if(checked){ radio.attr('checked', 'checked') }

targ_div.append('br')

return button;
}

</script>

https://d3js.org/d3.v3.min.js