• 每天一个JS 小demo之留言板。主要知识点:DOM方法的理解和运用


    <!DOCTYPE html>
    <html lang="en">
    <head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style type="text/css">
    .wrap {
    400px;
    margin: 30px auto;
    }
    textarea {
    display: block;
    100%;
    height: 60px;
    }
    input {
    display: block;
    60%;
    margin: 15px auto;
    }
    li {
    padding: 5px 10px;
    position: relative;
    word-break: break-all;
    }
    .red {
    color: #000;
    background: #f1f1f1;
    }
    .pink {
    color: #000;
    background: #ccc;
    }
    a {
    position: absolute;
    right: 0;
    top: -20px;
    background: yellow;
    color: #fff;
    }
    #list {
    margin: 0;
    padding: 0;
    list-style: none;
    font: 14px/26px "宋体";
    }
    .clos {
    position: absolute;
    top: 0;
    right: -50px;
    50px;
    color: #fff;
    background: #000;
    padding: 5px 0;
    text-decoration: none;
    text-align: center;
    }
    .clos:hover {
    box-shadow: 0 0 5px rgba(0,0,0,.5)
    }
    </style>
    <script type="text/javascript">
    window.onload = function(){
    var btn = document.querySelector('input');
    var text = document.querySelector('textarea');
    var list = document.querySelector('#list');
    var colors = ["red","pink"];
    var nub = 0;
    btn.onclick = function(){
    if(text.value.trim() == ""){
    alert("打点字吧");
    return false;
    }
    var li = document.createElement("li");
    li.innerHTML = text.value;
    // li.className = colors[nub%colors.length];
    /* 判断a标签已经被添加,就让a标签显示出来,否则就添加 */
    if(list.children[0]&&list.children[0].className=="red"){
    li.className = "pink";
    } else {
    li.className = "red";
    }
    var a = null;
    li.onmouseover = function(){
    if(a) {
    a.style.display = "block";
    } else {
    a = document.createElement("a");
    a.href = "javascript:;";
    a.className = "clos";
    a.innerHTML = "删除";
    a.onclick = function (){
    list.removeChild(this.parentNode);
    };
    this.appendChild(a);
    }
    };
    li.onmouseout = function(){
    a.style.display = "none";
    };
    list.insertBefore(li,list.children[0]);
    text.value = "";
    nub++;
    };
    };
    </script>
    </head>
    <body>
    <div>
    <div class="wrap">
    <textarea id="text"></textarea>
    <input type="button" value="创建元素">
    <ul id="list"></ul>
    </div>
    </body>
    </html>

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  • 原文地址:https://www.cnblogs.com/catEatBird/p/6995630.html
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