function addnode(){

var tbody = document.getElementById("table").lastChild;

var tr = document.createElement("tr");

//添加一个input标签，setAttribute添加属性，为什么不行呀

var td1 = document.createElement("td");

var input = document.createElement("input");

input.setAttribute("type","text");

td1.appendChild("input");

var td2 = document.createElement("td");

var input2 = document.createElement("input");

input2.setAttribute("type","text");

td2.appendChild("input2");

var td3 = document.createElement("td");

var a = document.createElement("a");

a.setAttribute("href","javascript:;");

a.setAttribute("onclick","deletenode(this)");

a.innerHTML="删除";

td3.appendChild(a);

tr.appendChild(td1);

tr.appendChild(td2);

tr.appendChild(td3);

tbody.appendChild(tr);

}