我需要用cookie或localstorage保存下拉列表中的选择。然后根据选择，我必须更改<href>中包含的链接
如果有人愿意帮助我，我提前感谢他。
试试这个脚本：
<!DOCTYPE html>
<html>
<body>
<a href="https://defaulturl.com" id="demo">Link</a>
<select name="options" id="options">
<option value="default" selected="false">Keep default</option>
<option value="alternative">Use alternative</option>
</select>
<button onclick="setcookie()">Set preference</button>
<script>
window.onload = function() {
var cookiecount = document.cookie.split("; ");
var foundcookie = false;
for (var i = 0; i < cookiecount.length; i++) {
var cookie = cookiecount[i].split("=");
if (cookie[0] == "preference") {
foundcookie = cookie[1]
}
}
if (foundcookie == false) {
document.cookie = "preference=default; ";
var a = document.getElementById("demo");
a.href = "https://defaulturl.com";
} else if (foundcookie == "alternative") {
var a = document.getElementById("demo");
a.href = "https://alternativeurl.com";
} else {
var a = document.getElementById("demo");
a.href = "https://defaulturl.com";
}
}
function setcookie() {
var userpreference = document.getElementById("options").value;
document.cookie = "preference=" + userpreference.toString() + "; ";
if (userpreference == "default") {
var a = document.getElementById("demo");
a.href = "https://defaulturl.com";
} else {
var a = document.getElementById("demo");
a.href = "https://alternativeurl.com";
}
}
</script>
</body>
</html>
它将检查cookie是否已存储，如果未存储，则将其设置为默认值。然后它将检查cookie值，并相应地更改链接。还有一个功能可以通过下拉菜单重置cookie。