js Create canvas,该如何解决

js Create canvas
我用如下代码创建一个canvas，为什么不对？

JScript code

var link=document.createElement("a");    link.id=0;    link.href="#";    link.onclick=function(id,event){         switchPicTo(link.id,event);          return false;};    document.getElementById("picbar").appendChild(link);    var linkcanvas=document.createElement("canvas");    linkcanvas.id="slidepic0";;    linkcanvas.width='100px';    linkcanvas.height='90px';    linkcanvas.style="background:white;margin-top:4px;margin-left:8px;";    link.appendChild(linkcanvas);

HTML code

<div id="picbar"></div><script type="text/javascript">var link=document.createElement("a");    link.id=0;    link.href="#";    link.onclick=function(id,event){         switchPicTo(link.id,event);          return false;};    document.getElementById("picbar").appendChild(link);    var linkcanvas=document.createElement("canvas");    linkcanvas.id="slidepic0";;    linkcanvas.width='100';    linkcanvas.height='90';   // linkcanvas.cssText="background:red;margin-top:4px;margin-left:8px;";    linkcanvas.style.background="red";   link.appendChild(linkcanvas);</script>