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How to set JSON format to HTML5 data attributes in the jQuery

Posted by: admin November 30, 2017 Leave a comment


I’m trying these HTML

<div data-params="{a: 1, b: '2'}" id="TEST1"></div>
<div data-params='{"a": 1, "b": "2"}' id="TEST2"></div>

Then I use data() method in the jQuery

$('#TEST1').data('params'); //return a string
$('#TEST2').data('params'); //return a object

But TEST1 it’s not a return object, but a string, it can only return object TEST2.
But I want to get a object by TEST1, How do I do it?


Finally, I choose to write a function to achieve their own needs

$.fn.data2 = function(key, value)
    if (value === undefined) 
        var data = $(this).data(key);
        if (typeof(data) === 'string') 
            var _data = data.replace(/^[\s\r\n]*/g, '').replace(/[\s\r\n]*$/g, '');
            if (_data.match(/\{.*\}/) || _data.match(/\[.*\]/)) {
                try {
                    _data = (new Function( 'return ' + data ))();
                    if (typeof(_data) == 'object') {
                        $(this).data(key, _data);
                        data = _data;
                } catch(ex) {}
        return data;
    return $(this).data(key, value);

In order to be parsed as an object, the data attribute must be a well formed JSON object.

In your case you just need to quote the object keys (as you do in the second object). Try:

<div data-params='{"a": 1, "b": "2"}' id="TEST1"></div>

For more info see the data method docs, the relevant part is this one (emphasis mine):

Every attempt is made to convert the string to a JavaScript value
(this includes booleans, numbers, objects, arrays, and null) otherwise
it is left as a string… …When the
data attribute is an object (starts with '{') or array (starts with
'[') then jQuery.parseJSON is used to parse the string; it must follow
valid JSON syntax including quoted property names.


You can escape the inner quotes:

<div data-params="{&quot;a&quot;: 1, &quot;b&quot;: &quot;2&quot;}" id="TEST2"></div>

But there is nothing wrong with your second method:

<div data-params='{"a": 1, "b": "2"}' id="TEST2"></div>

I would use that.


Try this one. It’s how Uikit parse data attribute json. Hope this will helpful

function str2json(str, notevil) {
  try {
    if (notevil) {
      return JSON.parse(str
                        .replace(/([$\w]+)\s*:/g, function(_, $1){return '"'+$1+'":';})
                        .replace(/'([^']+)'/g, function(_, $1){return '"'+$1+'"';})
    } else {
      return (new Function("", "var json = " + str + "; return JSON.parse(JSON.stringify(json));"))();
  } catch(e) { return false; }

function options(string) {
  if (typeof string !='string') return string;

  if (string.indexOf(':') != -1 && string.trim().substr(-1) != '}') {
    string = '{'+string+'}';

  var start = (string ? string.indexOf("{") : -1), options = {};

  if (start != -1) {
    try {
      options = str2json(string.substr(start));
    } catch (e) {}

  return options;

var paramsData = document.querySelectorAll('[data-params]')[0].dataset.params;

var optionsParsed = options(paramsData);

<!doctype html>
<html lang="en">
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <div data-params="{hello: 'world'}"></div>