HTML学习笔记（6）
利用dom操作实现，对一个表格的增删改查
代码如下：
todolist.html
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><link rel="stylesheet" href="todolist.css"><script src="todolist.js" defer></script>
</head>
<body><div class="container"><div class = "top"><input type="text" class="content"><input type="button" value="添加" class="btn"></div><table border="1"><thead><tr><th>内容</th><th>操作</th></tr></thead><tbody></tbody></table></div>
</body>
</html>todolist.js
// 获取添加按钮
var btn = document.querySelector(".btn")
console.log(btn)// 获取输入框
var content = document.querySelector(".content")// 获取tbbody
var tbody = document.querySelector("tbody")// 定义标识
var flag = 1//修改存储的是哪条信息
var targetFlag = 0// 给添加按钮绑事件
btn.onclick = function(){if(btn.value == "修改") {var tds = document.querySelectorAll("tbody tr td:nth-child(1)")for(var i = 0; i < tds.length; i ++ ){if(tds[i].getAttribute("index") == targetFlag){tds[i].innerHTML = content.valuecontent.value=""btn.value = "添加"}}return}var text = content.value.trim() // trim去掉前后的空格if(text.length != 0){var tr = document.createElement("tr")var td1 = document.createElement("td")td1.setAttribute("index", flag)flag ++;td1.innerText = textvar td2 = document.createElement("td")td2.innerHTML = '<input type="button" value="完成" class="finish"><input type="button" value="删除" class="delete"><input type="button" value="修改" class="update"></input>'tr.append(td1)tr.append(td2)tbody.append(tr)content.value = "" //去掉输入框内的值} else {alert("请输入信息")}// 给完成按钮绑定事件var finish = document.getElementsByClassName("finish")for(var i = 0; i < finish.length; i ++ ){finish[i].onclick = function(){var target = this.parentNode.previousElementSiblingif(target.style.textDecoration == "line-through") {target.style.textDecoration = "none"target.style.color = "#000"this.value = "完成"this.style.borderColor = "#910000"this.style.color = "#910000" } else {target.style.textDecoration = "line-through"target.style.color = "#888"this.value = "恢复"this.style.borderColor = "#888"this.style.color = "#888"}}}var deleteBtn = document.getElementsByClassName("delete")for(var i = 0; i < deleteBtn.length; i ++ ){deleteBtn[i].onclick = function(){if(this.parentNode.previousElementSibling.style.textDecoration == "line-through") {if(confirm("确定要删除吗？")){var target = this.parentNode.parentNodetbody.removeChild(target)}} else {alert("努力完成吧")}}}var update = document.getElementsByClassName("update")for(var i = 0; i < update.length; i ++ ){update[i].onclick = function(){var target = this.parentNode.previousElementSiblingif(target.style.textDecoration == "line-through"){alert("已经完成辣，无需修改")content.value = ""btn.value = "添加"} else {content.value = target.innerTextbtn.value = "修改"targetFlag = target.getAttribute("index")}}}
}todolist.css
* {padding: 0;margin: 0;
}.container {width: 25%;margin: 150px auto;min-width: 200px;
}.top {display: flex;
}.top .content {width: 80%;border: 1px solid #910000;padding: 5px;/* 外轮廓去掉 */outline: none;border-radius: 5px 0 0 5px;
}.top .btn {width: 20%;border: 1px solid #910000;background: #910000;color: #fff;padding: 5px;border-radius: 0 5px 5px 0;cursor: pointer;
}.top .btn:hover {box-shadow: 1px 1px 3px #910000;
}table {/* 设置表格边框是否合并collapse相邻的单元格共用一个边框 separate */border-collapse: collapse;width: 100%;margin-top: 30px;text-align: center;border: 1px solid #fff;
}table thead tr {background: #910000;color: #fff;
}table thead tr th {padding: 5px;font-size: 14px;
}table tbody tr {background: #eee;font-size: 13px;
}table tbody tr td {padding: 5px;
}table tbody tr:nth-child(odd) {background: #ddd;
}table tbody tr td input {background: none;border: 1px solid #910000;padding: 2px 5px;font-size: 13px;color: #910000;/* 鼠标样式 */cursor: pointer;
}table tbody tr td input:hover {box-shadow: 1px 1px 3px #910000;
}