web存儲
阿新 • • 發佈：2017-07-17
web存儲
localStorage 對象存儲的數據沒有時間限制。數據以 鍵/值 對存在, web網頁的數據只允許該網頁訪問使用。
保存數據：localStorage.setItem(key,value);
讀取數據：localStorage.getItem(key);
刪除單個數據：localStorage.removeItem(key);
刪除所有數據：localStorage.clear();
得到某個索引的key：localStorage.key(index);
將用戶名和密碼保存到localstorage中，在頁面展示
<!DOCTYPE html><html>
<head>
<meta charset="UTF-8">
<title></title>
<style>
td {text-align: center;}
</style>
</head>
<body>
<label for="">用戶名：</label><input type="text" id="username" /><br>
<label for="">密 碼：</label><input type="password" id="password" /><br>
<button onclick="btn()">保存</button><button onclick="del()">清空用戶信息</button>
<div id="table-box" style="display: none;">
<table border="1" cellpadding="0" cellspacing="0" id="table" width="300" >
<caption>用戶信息表</caption>
<tr>
<th>序號</th>
<th>用戶名</th>
<th>密碼</th>
<th>操作</th>
</tr>
</table>
</div>
<script>
window.onload = function() { //讀取緩存
var str = ""; var Text = localStorage.getItem("T");
Text = JSON.parse(Text); //把字符串轉換成JSON對象
if(Text != null) { //localStorage不為空
show() var objs = Text.te; for(var i = 0; i < objs.length; i++) {
str += "<tr><td>" + (i + 1) + "</td><td>" + objs[i].name + "</td><td>" + objs[i].pd + "</td><td><button onclick=‘del_one("+objs[i].name+")‘>刪除</button></td></tr>";
}
document.getElementById("table").innerHTML += str;
}
} function btn() { //存入緩存
var u = document.getElementById("username").value; var b = document.getElementById("password").value; if(u != ‘‘ && b != ‘‘) {
add(u, b)
}
} function add(a, b) { //設置緩存
var Save = false; var Index = table.rows.length; var Text = localStorage.getItem("T");
Text = JSON.parse(Text); //將一個 JSON 字符串轉換為對象。
if(Text != null && Text != "underfind") { var objs = Text.te; for(var i = 0; i < objs.length; i++) { //遍歷緩存
Save = false; if(objs[i].name == a) { //統計緩存中相同數據個數
alert("用戶名已存在")
Save = true; break;
}
} if(!Save) { //如果條件為真，則執行
var str = "<tr><td>" + (Index) + "</td><td>" + a + "</td><td>" + b + "</td><td><button onclick=‘del_one("+a+")‘>刪除</button></td></tr>";
document.getElementById("table").innerHTML += str;
objs[objs.length] = {
num: Index,
name: a,
pd: b
};
}
} else {
show() var str = "<tr><td>" + (Index) + "</td><td>" + a + "</td><td>" + b + "</td><td><button onclick=‘del_one("+a+")‘>刪除</button></td></tr>";
document.getElementById("table").innerHTML += str; var Text = { //要存儲的JSON對象
te: [{
num: Index,
name: a,
pd: b
}]
}
}
Text = JSON.stringify(Text); //將JSON對象轉化成字符串
localStorage.setItem("T", Text); //用localStorage保存轉化好的的字符串
document.getElementById("username").value = ‘‘;
document.getElementById("password").value = ‘‘;
} function del() { //清空緩存
localStorage.clear();
window.location.reload();
} function show(){
document.getElementById("table-box").style.display ="block";
} function del_one(event){
var Text = localStorage.getItem("T");
Text = JSON.parse(Text); //把字符串轉換成JSON對象
var objs = Text.te; for(var i = 0; i < objs.length; i++) { if(objs[i].name == event) { //說明存在該用戶
objs.splice(i, 1); //刪除某一條數據
Text = JSON.stringify(Text); //將JSON對象轉化成字符串
localStorage.setItem("T", Text); //用localStorage保存轉化好的的字符串
}
} if(objs.length == "0"){localStorage.clear();}
window.location.reload();
} </script>
</body></html>web存儲