Bind JSON object to HTML element

Question

I want to bind a JSON object to a HTML element.

e.g.

I have a object "person" with the attributes "firstName", "lastName"

<div class="person-list">
  <div class="person-list-item">
    <div>John</div>    ---> bind it to person.firstName
    <div>Smith</div>   ---> bind it to person.lastName
  </div>
</div>

so, if a value of the HTML elements gets changed, then will also the object person gets updated.

is this possible in any way?

i use:

• jquery
• ASP.NET MVC 3

Solution 1

If you'll be doing this a lot in your application, you may want to bring in a library such as the excellent Knockout.js which uses MVVM to do bindings as you describe.

Your markup would look something like this:

<div data-bind="text: firstName"></div>
<div data-bind="text: lastName"></div>

And in your JavaScript:

function MyViewModel() {
    this.firstName = "John";
    this.lastName = "Smith";
}

ko.applyBindings(new MyViewModel());

You can also use a data set if there are many "people." Try out this tutorial if you would like to learn how to do that: Working with Lists and Collections.

Other useful links:

• Introduction tutorial
• Excellent demo video (about 30 minutes)

Solution 2

First, add id attributes to your markup (you could do this with the DOM but for clarity's sake ids are probably best suited for this example):

<div class="person-list-item">
   <div id="firstname">John</div>
   <div id="lastname">Smith</div>
</div>

Use a jQuery event handler to update the fields whenever they are modified (this is an inefficient solution but gets the job done- worry about optimizing once you have something functional):

// declare your object
function person(firstn, lastn) {
    this.firstname = firstn;
    this.lastname = lastn;
}

var myGuy = new person("John", "Smith");

$(document).ready(function () {
    $("#firstname").change(function () {
        myGuy.firstname = $("#firstname").val();
    });

    $("#lastname").change(function () {
        myGuy.lastname = $("#lastname").val();
    });

    // etc...
});

Now every time the fields are updated your object will be too.

Solution 3

Simple one-way approach using jquery...

    var resp = your_json_data;
    $(function () {
        $(".jsondata").each(function () {
            $(this).html(eval($(this).attr("data")));
        });
    });

then in the page...

 <span class="jsondata" data="resp.result.formatted_phone_number" />

Solution 4

You can parse the JSON to turn it into a JavaScript object:

var data = $.parseJSON(json_string);
// or without jQuery:
var data = JSON.parse(json_string);

If I understood your question correctly, you should have JSON that look like this:

[
    {
        "firstName": "John",
        "lastName": "Smith"
    },
    {
        "firstName": "Another",
        "lastName": "Person"
    } // etc
]

So you can just loop through the people like so:

$(document).ready(function() {
    var str = '[{"firstName":"John","lastName":"Smith"},{"firstName":"Another","lastName": "Person"}]',
        data = $.parseJSON(str);
    $.each(data, function() {
        var html = '<div class="person-list-item"><div>' + this.firstName + '</div><div>' + this.lastName + '</div></div>';
        $('#person-list').append(html);
     });
});​

Fiddle: http://jsfiddle.net/RgdhX/2/

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