CODEWITHSUNDEEP
javascriptjsonhtmlscript-tag
ChuckE
ChuckE

Reputation: 5688

HTML/Javascript: how to access JSON data loaded in a script tag with src set

I have this JSON file I generate in the server I want to make accessible on the client as the page is viewable. Basically what I want to achieve is:

I have the following tag declared in my html document: 

<script id="test" type="application/json" src="http://myresources/stuf.json">

The file referred in its source has JSON data. As I've seen, data has been downloaded, just like it happens with the scripts.

Now, how do I access it in Javascript? I've tried accessing the script tag, with and without jQuery, using a multitude of methods to try to get my JSON data, but somehow this doesn't work. Getting its innerHTML would have worked had the json data been written inline in the script. Which it wasn't and isn't what I'm trying to achieve.

Remote JSON Request after page loads is also not an option, in case you want to suggest that.

Upvotes: 122

Views: 207286

Answers (10)

Rapha&#235;l Benzazon
Rapha&#235;l Benzazon

Reputation: 11

While not being supported, there is an common alternative to get json into javascript. You state that "remote json request" it is not an option but you may want to consider it since it may be the best solution there is.
If the src attribute was supported, it would be doing a remote json request, so I don't see why you would want to avoid that while actively seeking to do it in an almost same fashion.

Solution :

<script>
    async function loadJson(){
        const res = await fetch('content.json');
        const json = await res.json();
    }
    loadJson();
</script>

Advantages

  • allows caching, make sure your hosting/server sets that up properly
  • on chrome, after profiling using the performance tab, I noticed that it has the smallest CPU footprint compared to : inline JS, inline JSON, external JS.

Upvotes: 0

kockburn
kockburn

Reputation: 17636

While it's not currently possible with the script tag, it is possible with an iframe if it's from the same domain.

<iframe
id="mySpecialId"
src="/my/link/to/some.json"
onload="(()=>{if(!window.jsonData){window.jsonData={}}try{window.jsonData[this.id]=JSON.parse(this.contentWindow.document.body.textContent.trim())}catch(e){console.warn(e)}this.remove();})();"
onerror="((err)=>console.warn(err))();"
style="display: none;"
></iframe>

To use the above, simply replace the id and src attribute with what you need. The id (which we'll assume in this situation is equal to mySpecialId) will be used to store the data in window.jsonData["mySpecialId"].

In other words, for every iframe that has an id and uses the onload script will have that data synchronously loaded into the window.jsonData object under the id specified.

I did this for fun and to show that it's "possible' but I do not recommend that it be used.

Here is an alternative that uses a callback instead.

<script>
    function someCallback(data){
        /** do something with data */
        console.log(data);

    }
    function jsonOnLoad(callback){
        const raw = this.contentWindow.document.body.textContent.trim();
        try {
          const data = JSON.parse(raw);
          /** do something with data */
          callback(data);
        }catch(e){
          console.warn(e.message);
        }
        this.remove();
    }
</script>
<!-- I frame with src pointing to json file on server, onload we apply "this" to have the iframe context, display none as we don't want to show the iframe -->
<iframe src="your/link/to/some.json" onload="jsonOnLoad.apply(this, someCallback)" style="display: none;"></iframe>

Tested in chrome and should work in firefox. Unsure about IE or Safari.

Upvotes: 8

hossein sedighian
hossein sedighian

Reputation: 2063

place something like this in your script file json-content.js

var mainjson = { your json data}

then call it from script tag 

<script src="json-content.js"></script>

then you can use it in next script

<script>
console.log(mainjson)
</script>

Upvotes: 7

Karan
Karan

Reputation: 41

I agree with Ben. You cannot load/import the simple JSON file.

But if you absolutely want to do that and have flexibility to update json file, you can

my-json.js

   var myJSON = {
      id: "12ws",
      name: "smith"
    }

index.html

<head>
  <script src="my-json.js"></script>
</head>
<body onload="document.getElementById('json-holder').innerHTML = JSON.stringify(myJSON);">
  <div id="json-holder"></div>
</body>

Upvotes: 4

DominicTurner
DominicTurner

Reputation: 51

Another alternative to use the exact json within javascript. As it is Javascript Object Notation you can just create your object directly with the json notation. If you store this in a .js file you can use the object in your application. This was a useful option for me when I had some static json data that I wanted to cache in a file separately from the rest of my app.

    //Just hard code json directly within JS
    //here I create an object CLC that represents the json!
    $scope.CLC = {
        "ContentLayouts": [
            {
                "ContentLayoutID": 1,
                "ContentLayoutTitle": "Right",
                "ContentLayoutImageUrl": "/Wasabi/Common/gfx/layout/right.png",
                "ContentLayoutIndex": 0,
                "IsDefault": true
            },
            {
                "ContentLayoutID": 2,
                "ContentLayoutTitle": "Bottom",
                "ContentLayoutImageUrl": "/Wasabi/Common/gfx/layout/bottom.png",
                "ContentLayoutIndex": 1,
                "IsDefault": false
            },
            {
                "ContentLayoutID": 3,
                "ContentLayoutTitle": "Top",
                "ContentLayoutImageUrl": "/Wasabi/Common/gfx/layout/top.png",
                "ContentLayoutIndex": 2,
                "IsDefault": false
            }
        ]
    };

Upvotes: 1

Vitaliy Kaplich
Vitaliy Kaplich

Reputation: 49

If you need to load JSON from another domain: http://en.wikipedia.org/wiki/JSONP
However be aware of potential XSSI attacks: https://www.scip.ch/en/?labs.20160414

If it's the same domain so just use Ajax.

Upvotes: 3

L.Grillo
L.Grillo

Reputation: 981

Check this answer: https://stackoverflow.com/a/7346598/1764509

$.getJSON("test.json", function(json) {
    console.log(json); // this will show the info it in firebug console
});

Upvotes: 2

btx9000
btx9000

Reputation: 474

It would appear this is not possible, or at least not supported.

From the HTML5 specification:

When used to include data blocks (as opposed to scripts), the data must be embedded inline, the format of the data must be given using the type attribute, the src attribute must not be specified, and the contents of the script element must conform to the requirements defined for the format used.

Upvotes: 15

Lea Rosema
Lea Rosema

Reputation: 1150

Another solution would be to make use of a server-side scripting language and to simply include json-data inline. Here's an example that uses PHP:

<script id="data" type="application/json"><?php include('stuff.json'); ?></script>
<script>
var jsonData = JSON.parse(document.getElementById('data').textContent)
</script>

The above example uses an extra script tag with type application/json. An even simpler solution is to include the JSON directly into the JavaScript:

<script>var jsonData = <?php include('stuff.json');?>;</script>

The advantage of the solution with the extra tag is that JavaScript code and JSON data are kept separated from each other.

Upvotes: 23

Ben Lesh
Ben Lesh

Reputation: 108501

You can't load JSON like that, sorry.

I know you're thinking "why I can't I just use src here? I've seen stuff like this...":

<script id="myJson" type="application/json">
 { 
   name: 'Foo' 
 }
</script>

<script type="text/javascript">
    $(function() {
        var x = JSON.parse($('#myJson').html());
        alert(x.name); //Foo
     });
</script>

... well to put it simply, that was just the script tag being "abused" as a data holder. You can do that with all sorts of data. For example, a lot of templating engines leverage script tags to hold templates.

You have a short list of options to load your JSON from a remote file:

  1. Use $.get('your.json') or some other such AJAX method.
  2. Write a file that sets a global variable to your json. (seems hokey).
  3. Pull it into an invisible iframe, then scrape the contents of that after it's loaded (I call this "1997 mode")
  4. Consult a voodoo priest.

Final point:

Remote JSON Request after page loads is also not an option, in case you want to suggest that.

... that doesn't make sense. The difference between an AJAX request and a request sent by the browser while processing your <script src=""> is essentially nothing. They'll both be doing a GET on the resource. HTTP doesn't care if it's done because of a script tag or an AJAX call, and neither will your server.

Upvotes: 134

Related Questions