js

1.仿微博发表评论

1)css样式

*{
    margin:0;
    padding:0;
}
a{
    text-decoration: none;
}
input{
    border:0;
}
li{
    list-style: none;
}
.container{
    width:800px;
    margin:0 auto;
    /*border:1px solid #000;*/
    padding:20px;
}
input{
    border:1px solid #666;
    width:100%;
    height:100px;
    padding-left:10px;
}
.content>p{
    font-weight: bold;
    font-size: 20px;
    padding:10px;
}
.content>p>span{
    font-weight: normal;
    font-size:14px;
    margin-left:400px;
}
.content>button{
    width:70px;
    height:40px;
    line-height: 40px;
    background: #e4393c;
    border-radius: 5px;
    border:0;
    font-size: 16px;
    font-weight: bold;
    color:#fff;
    margin-top:10px;
    margin-left:90%;
}
.main{
    width:100%;
    border:1px solid #000;
    overflow: hidden;
    border-radius: 20px;
    margin-top:20px;
     padding:0 10px;
}
.main>img,.main>p{
     float:left;
}
.main>img{
    width:100px;
    height:100px;
}
.main>p{
    width:500px;
    height:100px;
    line-height: 100px;
    padding-left:50px;
    /*border:1px solid #000;*/
}
.main>button{
    width:70px;
    height:40px;
    line-height: 40px;
    background: #e4393c;
    border-radius: 5px;
    border:0;
    font-size: 16px;
    font-weight: bold;
    color:#fff;
    float:right;
    margin-top:30px;
}

2)div

<div class='container'>
    <div class='content'>
        <p>你想对楼主说点什么 <span>你最多可输入30个字符</span></p>
        <input type="text" name="" placeholder="请输入你想要说的内容">
        <button>发表</button>
    </div>
</div>

3)script

把图片做成随机数

var btn=document.querySelector('.content>button');
btn.onclick=function(){
    var inputVal=document.querySelector('.content>input').value;
    //动态创建元素：
    //动态创建div
        var div=document.createElement('div');
        div.className='main';
        var img=document.createElement('img');
        var arr=['img/1.jpg','img/2.jpg','img/3.jpg'];
        var num=Math.floor(Math.random()*3);
        img.src=arr[num]; 
        div.appendChild(img);
        var p=document.createElement('p');
        p.innerHTML=inputVal;
        document.querySelector('.content>input').value='';
        div.appendChild(p);
        var button=document.createElement('button');
        button.innerHTML='删除';
        button.onclick=function remov(){
            this.parentElement.parentElement.removeChild(this.parentElement);
        }
        div.appendChild(button);
        document.querySelector('.container').appendChild(div);     
}