所以，我有我的代码，我知道问题所在，但我不知道如何解决它。
每当您加载页面时，我的“btc”变量都会重新定义，使其始终加载为 1，我如何让 btc 加载一次，并且在 cookie“用户名”的生命周期内只加载一次？
(我不能再向变量添加'btc'，因为当我刷新它时，它总是将它重新定义为一个。)
<html>
<body onload="abu()">
<style>
.column {
background-color: lightgrey;
width: 120px;
border: 12px solid blue;
padding: 19.5px;
margin: 19.5px;
}
.col {
background-color: lightgrey;
width: 120px;
border: 12px solid red;
padding: 19.5px;
margin: 19.5px;
}
body{
background-image: url('https://cdn.shutterstock.com/shutterstock/videos/2669351/thumb/1.jpg');
background-size: cover;
}
#customers {
font-family: "Trebuchet MS", Arial, Helvetica, sans-serif;
border-collapse: collapse;
width: 100%;
}
#customers td, #customers th {
border: 1px solid #ddd;
padding: 8px;
}
#customers tr:nth-child(even){background-color: #f2f2f2;}
#customers tr:hover {background-color: #ddd;}
#customers th {
padding-top: 12px;
padding-bottom: 12px;
text-align: left;
background-color: #ff2a00;
color: white;
}
</style>
<center><h1>Dashboard</h1></center>
<div class="column"><p id="btc">Satoshi: 0</p></div>
<div class="col"><p id="dash">WIP</p></div>
<!---<table id="customers">
<tr>
<th>Name</th>
<th>Link</th>
<th>Payout</th>
</tr>
<tr>
<td>FirstSat</td>
<td><button onclick="foo()"><img src="kop.png" width="32" height="28">Here</button></td>
<td>1</td>
</tr>
</table>---!>
<button onclick="testsan()">a</button>
<script>
var btc = 1;
function update()
{
document.getElementById('btc').innerHTML = "Satoshi: " + btc;
}
abu();
function testsan() {
var username = parseInt(getCookie("username"));
btc = btc + 1
document.getElementById('btc').innerHTML = "Satoshi: " + btc;
setCookie("username", username + 1);
}
function abu() {
var username = parseInt(getCookie("username"));
if (isNaN(username)) {
username = 0;
}
document.getElementById('btc').innerHTML = "Satoshi: " + btc;
setCookie("username", username + 1);
}
function setCookie(cname,cvalue,exdays) {
var d = new Date();
d.setTime(d.getTime() + (exdays*24*60*60*1000));
var expires = "expires=" + d.toGMTString();
document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}
function getCookie(cname) {
var name = cname + "=";
var decodedCookie = decodeURIComponent(document.cookie);
var ca = decodedCookie.split(';');
for(var i = 0; i < ca.length; i++) {
var c = ca[i];
while (c.charAt(0) == ' ') {
c = c.substring(1);
}
if (c.indexOf(name) == 0) {
return c.substring(name.length, c.length);
}
}
return "";
}
function checkCookie() {
var user=getCookie("username");
if (user != "") {
alert("Welcome again " + user);
} else {
alert('user = "' + user + '"');
if (user != undefined) {
setCookie("username", btc);
}
}
}
</script>
</html>
如能提供帮助，将不胜感激! ^^
最佳答案
在checkCookie , 如果用户的 cookie 存在, 检索 btc来自 localStorage 的值(如果存在)。否则，设置 btc值为 1，均在 localStorage 中并在变量中。例如，假设您运行 checkCookie在每次页面加载时(或在使用 btc 之前:
let btc;
function checkCookie() {
var user=getCookie("username");
if (user != "") {
alert("Welcome again " + user);
btc = Number(sessionStorage.btc || 1);
} else {
alert('user = "' + user + '"');
if (user != undefined) {
setCookie("username", btc);
}
btc = 1;
}
}
然后在testsan , 分配给 localStorage :
function testsan() {
btc = btc + 1;
localStorage.btc = btc;
// ...
如果您还想跟踪一个单独的 btc对于每个用户，您必须创建一个用户的对象 和btc值，并在设置或获取 localStorage 时对其进行字符串化/解析.
关于javascript - 如何在 JS 中定义一次变量？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/50710686/