js实现开关灯效果

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style type="text/css">
			div{
				float: left;
				margin: 20px;
				border: 1px solid #0088D3;
			}
		</style>
		<script type="text/javascript">
			window.onload = function(){
				// 两个按钮
				var aImg1 = document.getElementById('img1');
				var btnK1 = document.getElementById('btn1K');
				var btnG1 = document.getElementById('btn1G');
				btnK1.onclick = function(){
					aImg1.src = './images/off.png';
				}
				btnG1.onclick = function(){
					aImg1.src = './images/on.png';
				}
				
				// 一个按钮
				var aImg2 = document.getElementById('img2');
				var btn = document.getElementById('btn');
				
				var onoff = true;
				
				btn.onclick = function(){
					// if(aImg2.src.match("off")){  //图片名匹配  第二种方法
					// 	// console.log(aImg2.src);
					// 	aImg2.src = './images/on.png';
					// 	btn.innerHTML = '关灯';
					// }else{
					// 	aImg2.src = './images/off.png';
					// 	btn.innerHTML = '开灯';
					// }
					
					if(onoff){
						// console.log(aImg2.src);
						aImg2.src = './images/on.png';
						btn.innerHTML = '关灯';
					}else{
						aImg2.src = './images/off.png';
						btn.innerHTML = '开灯';
					}
					onoff = !onoff;
					// console.log(nu);
				}
				
				// 没有按钮
				var aImg3 = document.getElementById('img3');
				aImg3.onclick = function(){
					if(aImg3.src.match("off")){
						aImg3.src = './images/on.png';
					}else{
						aImg3.src = './images/off.png';
					}
				}
			}
			
		</script>
	</head>
	<body>
		<div class="box1">
			<button type="button" id="btn1K">关灯</button>
			<img src="./images/off.png" alt="t" id="img1">
			<button type="button" id="btn1G">开灯</button>
		</div>
		<div class="box2">
			<img src="./images/off.png" alt="t" id="img2">
			<button type="button" id="btn">开灯</button>
		</div>
		<div class="box3">
			<img src="./images/off.png" alt="t" id="img3">
		</div>
	</body>
</html>