这里是以前篇附件上传为前提，比较原始的一种方式，但最容易修改

 function addfile(){
        	
        	   var aElement = document.getElementById("usertable");
        	   var dd = document.createElement("tr");
        	   var tdobj=document.createElement("td");
        	   tdobj.innerText="请上传附件";
        	  
        	dd.appendChild(tdobj);
        	var tdobj3=document.createElement("td");
        	tdobj3.setAttribute("colspan", "2");
        	
        	var inp2 = document.createElement("input");
        	 inp2.setAttribute("type", "file");
        	 inp2.setAttribute("name", "file");
        	
        	 tdobj3.appendChild(inp2);
        	 dd.appendChild(tdobj3);
        	 var tdobj4=document.createElement("td");
        	  var sp=document.createElement("a");
        	    sp.setAttribute("title", "删除该附件");
        	 if(sp.addEventListener)
        	   {
        	    sp.addEventListener("click", function(){deteFile123(sp);},false);
        	   }
        	   else if(sp.attachEvent)//IE内核监听
        	   {
        	    sp.attachEvent("onclick", function(){deteFile123(sp);});
        	   }
        	   else
        	   {
        	     sp.click = function(){deteFile123(sp);};
        	   }
        	 var ff = document.createElement("span");
        	 ff.innerText="删除附件";
        	 sp.appendChild(ff);
        	 tdobj4.appendChild(sp);
        	 dd.appendChild(tdobj4);
        	 
        	 aElement.appendChild(dd);
        	  }
        	  //删除附件
        	  function deteFile123(obj){
        	   //alert(id);
        	   var aElement = document.getElementById("usertable");
        	   obj = obj.parentNode.parentNode;
        	      aElement.removeChild(obj);
        	  }