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);     
}

2.仿新浪微博发布评论js代码

1)css样式

.main{
    width: 800px;
    margin:20px auto;
}
span{
    display: inline-block;
    width: 200px;
    height: 25px;
    line-height: 25px;
    vertical-align: middle;
    text-align: left;
    margin-bottom: 10px;
}

.tag{
    font-size: 13px;
    margin-left: 370px;
    vertical-align: bottom;
    text-align: center;
    margin-bottom: 0;
}
.text{
    width: 750px;
    height: 180px;
    margin:0 auto;
    resize:none;
}

input{
    display: inline-block;
    width: 80px;
    height: 50px;
    background: #E2526F;
    border: 0;
    margin-left: 670px;
    margin-top: 10px;
}

.creatediv{
    width: 675px;
    height: 80px;
    border: 1px solid gray;
    position: relative;
    margin-top: 10px;
    padding-left: 75px;
}

.createinput{
    width: 80px;
    height: 30px;
    position:absolute;
    right: 5px;
    bottom:5px;
}

.createimg{
    width: 50px;
    height: 50px;
    position: absolute;
    top: 15px;
    left: 15px;
}

.createdivs{
    width:600px;
    height:50px;
    position: absolute;
    top: 15px;
    left: 85px;
}

2)div

<div class="main">
    <span>你想对楼主说点什么</span>
    <span class="tag">你最多可以输入30个字符</span>
    <textarea id="text" cols="30" rows="10" maxlength="30" class="text" spellcheck="false"></textarea><br>
    <input type="button" value="发 表" id="ipt">
    <div id="txt" ></div>
</div>

3)script

var textarea=document.getElementById("text");
var ipt=document.getElementById("ipt");
var txt=document.getElementById("txt");
ipt.onclick=function(){
    var txtValue=textarea.value;
    if(txtValue.length>0){
        var divs=document.createElement("div");
        var imgs=document.createElement("img");
        var ps=document.createElement("p");
        var inputs=document.createElement("input");
        divs.setAttribute("class","creatediv");
        imgs.setAttribute("class","createimg");
        ps.setAttribute("class","createdivs");
        inputs.setAttribute("class","createinput");
        img.src="pic/1.jpg";
        input.type="button";
        inputs.value="删除";
        ps.innerHTML=txtValue;
        divs.appendChild(imgs);
        divs.appendChild(ps);
        divs.appendChild(inputs);
        if(txt.children.length==0){
            txt.appendChild(divs);
        }else{
            txt.insertBefore(divs,get_firstChild(txt));
        }

        inputs.onclick=function(){
            this.parentElement.parentElement.removeChild(this.parentElement)
        }
    }
}

var textarea=document.getElementById("text");
    var inputs=document.getElementById("ipt");
    var txt=document.getElementById("txt");
    ipt.onclick=function(){
        var txtValue=textarea.value;
        if(txtValue.length>0){
            var divs=document.createElement("div");
            var imgs=document.createElement("img");
            var ps=document.createElement("p");
            var inputs=document.createElement("input");
            divs.setAttribute("class","creatediv");
            imgs.setAttribute("class","createimg");
            ps.setAttribute("class","createdivs");
            inputs.setAttribute("class","createinput");
            imgs.src="pic/1.jpg";
            inputs.type="butto";
            inputs.value="删除";
            ps.innerHTML=txtValue;
            divs.appendChild(imgs);
            divs.appendChild(ps);
            divs.appendChild(inputs);
            if(txt.children.length==0){
                txt.appendChild(divs)
            }else{
                txt.appendChild(divs,get_firstChild(txt));
            }

            inputs.onclick=function(){
                this.parentElement
                        .parentElement
                        .removeChild(this.parentElement)
            }

        }
    }