3 implementation methods for generating img tags with javascript (object, method, html)_javascript skills

<div id="d1"></div>
<script>
//HTML
function a(){
document.getElementById("d1").innerHTML="<img src='http://baike.baidu.com/cms/rc/240x112dierzhou.jpg'>";
}
a();
//方法
function b(){
var d1=document.getElementById("d1");
var img=document.createElement("img");
img.src="http://baike.baidu.com/cms/rc/240x112dierzhou.jpg";
d1.appendChild(img);
}
b();
//对象
function c(){
var cc=new Image();
cc.src="http://baike.baidu.com/cms/rc/240x112dierzhou.jpg";
document.getElementById("d1").appendChild(cc);
}
c();
</script>