<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta http-equiv="X-UA-Compatible" content="ie=edge" />
<title>Document</title>
<style>
*{margin: 0;padding: 0;}
.div{ 500px; min-height: 300px; border: 1px solid red; margin: auto; margin-top: 200px;}
.div .lyb{ 90%; margin: auto; display: block; border-bottom: 1px solid red; padding: 5px 0px;}
.div .div1{ 90%; border: 1px solid red; margin: 5px auto;}
.div .div1 p{ 100%; padding: 5px 0px; height: 30px; line-height: 30px; }
.div .div1 ul{ 100%;}
.div .div1 ul li{ 100%; height: 30px; padding: 5px 0px; line-height: 30px; list-style: none;margin-bottom: 10px; background: blanchedalmond;}
#wbk{resize: none; 90%;margin: auto; height: 100px; display: block;}
#btn{ 90%; height: 100px; margin: auto; display: block; margin-top: 5px;}
a{float: right}
span{float: right;}
</style>
</head>
<body>
<div class="div">
<p class="lyb">留言板</p>
<div class="div1">
<p class="p">请输入内容</p>
<ul>
</ul>
</div>
<textarea id="wbk"></textarea>
<input id="btn" type="button" value="发布留言" />
</div>
<script>
var p = document.getElementsByClassName("p")[0];
var ul = document.getElementsByTagName("ul")[0];
var wbk = document.getElementById("wbk");
var btn = document.getElementById("btn");
var num = 0;
btn.onclick = function(){
if(wbk.value.length != 0){
p.style.display = "none";
var li = document.createElement("li");
var em = document.createElement('em');
var a = document.createElement("a");
var span = document.createElement("span");
li.innerHTML = wbk.value;
li.insertBefore(em,li.firstChild);
a.innerHTML = "点击删除";
a.setAttribute("href","javascript:void(0)");
li.appendChild(a);
span.innerHTML = "第" + num + "个";
li.appendChild(span);
wbk.value = "";
ul.appendChild(li);
fn1();
fn2();
}else{
alert("请输入内容")
}
}
function fn1(){
var ali = document.getElementsByTagName('li');
var ee = document.getElementsByTagName('em');
for(var i=0;i<ali.length;i++){
ee[i].innerHTML = i + 1 + ".";
}
var ss = document.getElementsByTagName('span');
for(var i=0;i<ali.length;i++){
ss[i].innerHTML = "第" + (i + 1) + "个";
}
if(ali.length == 0){
p.style.display = "block";
}
}
function fn2(){
var aa = document.getElementsByTagName("a");
for(var i=0;i<aa.length;i++){
aa[i].onclick = function(){
this.parentNode.parentNode.removeChild(this.parentNode);
fn1();
}
}
}
</script>
</body>
</html>