如何基于用户的先前值设置默认值 [英] How to set a default value based on user's previous value
本文介绍了如何基于用户的先前值设置默认值的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想根据用户输入的内容获得默认值。例如，如果在输入中我输入 5，那么我希望在刷新页面时看到该输入的值为5，但是如果输入6，则我希望默认值为6。谢谢（我是begginer）
I want to have a default value based on what the user put before. For example, if in an input I put '5' I want to see that the value of that input is 5 when I refresh the page, but if I put 6 I want the default value to be 6. Thanks (i'm a begginer)
推荐答案
使用本地存储：
localStorage = window.localStorage;
localStorage.setItem('inputDefault', '5');
let inputDefault = localStorage.getItem('inputDefault');
下面是一个更实际的例子，我很快就总结道：
Here's a more practical example I quickly whipped up:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Local Storage Example</title>
<script type="text/javascript">
function setLocalStorageValue()
{
let myNumberInputField = document.getElementById('myNumberInput');
let myNewValue = myNumberInputField.value;
let localStorage = window.localStorage;
localStorage.setItem('defaultValue', myNewValue);
}
function getLocalStoredValue()
{
let localStorage = window.localStorage;
let defaultValue = localStorage.getItem('defaultValue');
let myNumberInputField = document.getElementById('myNumberInput');
myNumberInputField.value = defaultValue;
}
</script>
</head>
<body onload="getLocalStoredValue()">
<label>My Number Input
<input type="number" id="myNumberInput" value="0" onchange="setLocalStorageValue()">
</label>
</body>
</html>
这是否回答您的问题？请注意，我是如何在有问题的输入的onchange事件上写回本地存储的，并且是在加载html正文时从本地存储读取的。
Does this answer your question? Note how I am writing back to local storage on the onchange event of the input in question, and I read from local storage when the body of the html loads.
这篇关于如何基于用户的先前值设置默认值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
