如何附加到HTML5 localStorage？ [英] How to append to HTML5 localStorage?

问题描述

我做了一个

  localStorage.setItem（'oldData'，$ i（textbox）。 
  

设置键 oldData 的值为文本框中的值。

下一次在文本框中输入内容时，我想追加到已存在的 oldData
因此，如果我在我的文本框中输入苹果，然后输入橙子，则我的localStorage项 oldData 应该看起来像这样：

最初：

  Key |价值
 --------------------------- 
 oldData |苹果
  

现在：

  oldData |苹果橙子
  

我该如何追加？ 是否提供追加方法？

或者是否需要读取数据首先，在javascript中追加，然后回写？

解决方案

没有追加功能。尽管写一个不难：

 函数appendToStorage（name，data）{
 var old = localStorage.getItem （名称）; 
 if（old === null）old =; 
 localStorage.setItem（name，old + data）; 
} 
 
 appendToStorage（'oldData'，$ i（textbox）.value）; 
  

注意：定义一个函数 append 放在 localStorage 对象上。 然而，因为 localStorage 有一个 setter ，所以这是不可能的。如果您试图使用 localStorage.append = ... 定义一个函数，那么 localStorage 对象将解释此尝试作为在存储对象中保存名为追加的对象。

I do a

localStorage.setItem('oldData', $i("textbox").value);

to set the value of key oldData to the value in a textbox.

The next time something is entered to the textbox, I want to append to the already existing oldData.

So, if I enter apples and then oranges in my textbox, my localStorage key oldData should look like this:

Initially:

Key      |   Value
---------------------------
oldData  |  apples

Now:

oldData  |  apples oranges

How can I append? Is there an append method provided?

Or do I need to read the data first, append in javascript and then write back?

解决方案

There's no append function. It's not hard to write one though:

function appendToStorage(name, data){
    var old = localStorage.getItem(name);
    if(old === null) old = "";
    localStorage.setItem(name, old + data);
}

appendToStorage('oldData', $i("textbox").value);

Note: It makes more sense to define a function append on the localStorage object. However, because localStorage has a setter, this is not possible. If you were trying to define a function using localStorage.append = ..., the localStorage object will interpret this attempt as "Save an object called append in the Storage object".

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