19、javascript基础知识

来源：互联网发布：超级优化女主角有几个编辑：程序博客网时间：2024/06/10 02:10

1、几天接到了一个奇葩的需求，就是在鼠标滚轮滑动的时候，div要悬浮不动，因此这引起了我对于javascript知识的复习

首先从最基础的变量的类型开始

<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Insert title here</title><script type="text/javascript">    alert(undefined == null);</script></head><body>

以上alert会显示true

2、全选，全不选和反选感觉个人真的不是对代码有依赖，感觉如果能不敲代码就真的棒级了，因此将来想回家帮妈妈买货，感觉能

靠嘴挣钱总比，动手强

<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Insert title here</title></head><body>    <br />    <input type="checkbox" name="items" value="足球">足球    <input type="checkbox" name="items" value="篮球">篮球    <input type="checkbox" name="items" value="排球">排球    <input type="checkbox" name="items" value="谭倩">谭倩    <br />    <input type="button" id="checkAll" value="全选">    <input type="button" id="nocheckAll" value="全不选">    <input type="button" id="oppositeAll" value="反选">    <script type="text/javascript">        var checkButton = document.getElementById("checkAll");        checkButton.onclick = function() {            var items = document.getElementsByName("items");            for (var i = 0; i < items.length; i++) {                if (!items[i].checked) {                    items[i].checked = true;                }            }        }        var nocheckButton = document.getElementById("nocheckAll");        nocheckButton.onclick = function() {            var items2 = document.getElementsByName("items");            for (var i = 0; i < items2.length; i++) {                if (items2[i].checked) {                    items2[i].checked = false;                }            }        }        var oppcheckButton = document.getElementById("oppositeAll");        oppcheckButton.onclick = function() {            var items3 = document.getElementsByName("items");            for (var i = 0; i < items3.length; i++) {                if (items3[i].checked) {                    items3[i].checked = false;                } else {                    items3[i].checked = true;                }            }        }    </script></body></html>

3、点击关上，点击打开

<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Insert title here</title><style type="text/css">div {    display: none;}a {    background-color: orange;}.open {    display: block;}.close {    display: none;}p{    font: bolder;    font-family: cursive;    font-style: italic;    color: blue;    background-color: orange;}table, tr, td {    padding: 0px;}</style><script type="text/javascript">    function openDiv(a) {        var currentDiv = a.parentNode.getElementsByTagName("div")[0];        var divs = document.getElementsByTagName("div");        for (var i = 0; i < divs.length; i++) {            if (currentDiv == divs[i]) {                currentDiv.className = "open";            } else {                divs[i].className = "close";            }        }    }</script></head><body>    <table>        <tr>            <td><a onclick="openDiv(this)">高中同学</a>                <div>                    <p>大勇</p> <p>君宇</p> <p>茂川</p>                </div></td>        </tr>        <tr>            <td><a onclick="openDiv(this)" >初中同学</a>                <div>                    <p>浩晨</p> <p>孟凯妮</p> <p>李倩</p>                </div></td>        </tr>        <tr>            <td><a onclick="openDiv(this)">小学同学</a>                <div>                    <p>想不起来了</p>                </div></td>        </tr>        <tr>            <td><a onclick="openDiv(this)">大学同学</a>                <div>                    <p>王金鉴</p> <p>李俊峰</p> <p>王宝林</p>                </div></td>        </tr>    </table></body></html>

代码运行的结果如下所示

阅读全文

0 0