HTML 5 local storage

Can I save data to to either CSV or XML files on offline on cl开发者_如何学Pythonient-side via HTML5?

The offline storage is an internal storage. It is not meant to export some files to a specific format / specific folder on disk.

The web storage API stores data as [key,value] pair where both key,value are Strings.

So data in any format needs to adhere to this mechanism for local storage. So for example, if you have a JSON object like :

{
  name:'John',
  gender:'male'
}

You can store it (through JavaScript) after passing it as a string like :

localStorage.setItem("myObj","{name:'John',gender:'male'}");

For JSON objects, use JSON.stringify() to convert them to strings and use JSON.parse() to read them back.

You can use localstorage, but that only allows you to store something on browsers' internal storage (you cannot decide where and how to write data).

There's also a File API, but is at its very early stages and, by now, it doesn't allow to store files arbitrarily on the client:

HTML 5 File API

Let say you have created array or object like this.

var arrayOrObject = [{obj1:{name:John, age:16}},{obj2:{name:Jane, age:17}}];

you can save this data to local devices by using localStorage.

if (typeof(localStorage) == 'undefined' ) {
    alert('Your browser does not support HTML5 localStorage. Try upgrading.');
} 
else {
     try {                  
        localStorage.setItem("storedArrayOrObject", JSON.stringify(arrayOrObject));
                             //saves to the database, “key”, “value”                
    } catch (e) {
        if (e == QUOTA_EXCEEDED_ERR) {
            alert('Quota exceeded!'); //data wasn’t successfully saved due to quota exceed so throw an error
        }
    }
}

To get the data in Array or Object Structure:

 var getStoredArrayOrObject = JSON.parse(localStorage.getItem('storedArrayOrObject'));`

To remove the localStorage Data:

 localStorage.removeItem('storedArrayOrObject');

Don't recommend this but available:

 localStorage.clear();

You could save and export as csv like this... http://joshualay.net/examples/StamPad/StamPad.html