有js动态添加字节点为什么没有用啊？

Question

	var date=new Date();
	var datestr=date.getFullYear()+"年"+(date.getMonth()+1)+"月"+date.getDate()+"日";
	var cdiv=document.createElement("div");
	var father=document.getElementsByClassName("message_figure");
		cdiv.setAttribute("class","the_message");
		father.appendChild(cdiv);
	var cspan=document.createElement("span");
		cspan.addclass("class","people_name");
		cdiv.appendChild(cspan);
	var cimg=document.createElement("img");
		cimg.setAttribute("class","img_people");
		cspan.appendChild(cimg);
		cspan.innerHTML=name;
	var cspan2=document.createElement("span");
		cspan2.setAttribute("class","time");
		cspan2.innerHTML=datestr;
		cdiv.appendChild(cspan2);
	var cp=document.createElement("p");
		cp.setAttribute("class","message");
		cp.innerHTML=text;
		cdiv.appendChild(cp);

Answer 1

	var date=new Date();
	var datestr=date.getFullYear()+"年"+(date.getMonth()+1)+"月"+date.getDate()+"日";
	var cdiv=document.createElement("div");
	var father=document.getElementsByClassName("message_figure")[0];
		cdiv.setAttribute("class","the_message");
		father.appendChild(cdiv);
	var cspan=document.createElement("span");
		cspan.setAttribute("class","people_name");
		cdiv.appendChild(cspan);
	var cimg=document.createElement("img");
		cimg.setAttribute("class","img_people");
		cspan.appendChild(cimg);
		cspan.innerHTML=name;
	var cspan2=document.createElement("span");
		cspan2.setAttribute("class","time");
		cspan2.innerHTML=datestr;
		cdiv.appendChild(cspan2);
	var cp=document.createElement("p");
		cp.setAttribute("class","message");
		cp.innerHTML=text;
		cdiv.appendChild(cp);