Save data to local storage

2019-01-24 04:35发布

站内文章 / JavaScript
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问题:

I'm trying to set a bush of variables in local storage but the function doesn't run, I've tried to get the value but without luck, How can I save fields in Local storage?

function setPerson(){
var person = { 'name': getElementById('name'), 'photo': getElementById('photo')};

// Put the object into the storage
    alert(person);
    localStorage.setItem('person', JSON.stringify(person));
};

HTML In the HTML I'm from fields put values into tags and they are populated, but when I try to fetch them and save them nothing is happening...

I also tried to out fixed values in there and then the alert is displayed, but then it only says object and not the value

var testObject = { 'one': 1, 'two': 2, 'three': 3 };

// Put the object into storage
localStorage.setItem('testObject', JSON.stringify(testObject));

// Retrieve the object from storage
var retrievedObject = localStorage.getItem('testObject');
alert('retrievedObject: ', JSON.parse(retrievedObject));;

回答1:

You can use localStorage like this:

// Retrieve your data from locaStorage
var saveData = JSON.parse(localStorage.saveData || null) || {};

// Store your data.
function saveStuff(obj) {
  saveData.obj = obj;
  // saveData.foo = foo;
  saveData.time = new Date().getTime();
  localStorage.saveData = JSON.stringify(saveData);
}

// Do something with your data.
function loadStuff() {
  return saveData.obj || "default";
}

jsFiddle



回答2:

First, you should use console instead of alert.

And, if you want to use the retrieved object somewhere, you'd better store it in a variable:

var testObject = { 'one': 1, 'two': 2, 'three': 3 };
localStorage.setItem('testObject', JSON.stringify(testObject));
var retrievedObject = JSON.parse(localStorage.getItem('testObject'));
console.log('retrievedObject: ', retrievedObject);


回答3:

W3C Schools gives you detailed examples on how to work with html and local storage.

w3cSchools - Local Storage



回答4:

getElementById should be changed to

    document.getElementById

Also this will get you the entire DOM element. I assume you want what's inside the tag so i would say use 

    document.getElementById('name').innerHTML

instead. Just referencing the DOM element will give you a circular strucure error when you attempt to stringify it.

Sample code that i have confirmed works:

<html>
<head>
</head>
<body>
<p id="name">Hello</p>
<p id="photo">photo</p>
<script>

function setPerson(){
var person = { 'name': document.getElementById('name').innerHTML, 'photo':    document.getElementById('photo').innerHTML};

// Put the object into storage
localStorage.setItem('person', JSON.stringify(person));
}
setPerson()
</script>
</body>
</html>


回答5:

The problem is that getElementById returns an HTML element, which is an object.

Then, JSON.stringify will attempt to iterate its own properties.

But probably, they haven't any (unless you added them manually).

Since you say they are fields, you can try saving its value instead:

var person = {
    name: document.getElementById('name').value,
    photo: document.getElementById('photo').value
};


标签： javascript jquery local-storage
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