Access 'Data-' Attribute Without Jquery

Access 'data-' attribute without jQuery

On here I found this example:

<div id='strawberry-plant' data-fruit='12'></div>
<script>
    // 'Getting' data-attributes using getAttribute
    var plant = document.getElementById('strawberry-plant');
    var fruitCount = plant.getAttribute('data-fruit'); // fruitCount = '12'
    // 'Setting' data-attributes using setAttribute
    plant.setAttribute('data-fruit', '7'); // Pesky birds
</script>

So it would appear very doable.

Update: Since Microsoft is now (2020) phasing out the old Internet Explorer engine in favour of a Chromium based Edge, the dataset property is likely to work everywhere. The exception will, for a time, be organizations and corporate networks where IE is still forced. At the time of writing this though - jsPerf still shows the get/setAttribute method as being faster than using dataset, at least on Chrome 81.

Getting array out of data attribute without jQuery

jQuery's .data() method automatically tries to convert the string in your custom data attribute to whatever type it appears to be (in this case an array). JavaScript just treats it as a string, so you need to parse the string to get the same array output you get with jQuery. For example:

// jQuery approach
const jqtest = $('div').data('toshow');
console.log(jqtest);

// Plain JavaScript approach
const jstest = JSON.parse(document.querySelector('div').dataset.toshow);
console.log(jstest);

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div data-toshow='["tblp"]'></div>

How can I get the data-id attribute?

To get the contents of the attribute data-id (like in <a data-id="123">link</a>) you have to use

$(this).attr("data-id") // will return the string "123"

or .data() (if you use newer jQuery >= 1.4.3)

$(this).data("id") // will return the number 123

and the part after data- must be lowercase, e.g. data-idNum will not work, but data-idnum will.

Store Object in data-attribute without jQuery

Use JSON.stringify() before storing the data in the attribute. It is basically serializing the data into a string.

var div = document.getElementById("testDiv");
var obj = JSON.stringify({name: "Test1", value: 100});
div.setAttribute("data-obj", obj);

var arrayAsJSON = JSON.stringify([59, 40, 3, 2, 1, 0]);
div.setAttribute("data-arr", arrayAsJSON);

Then use JSON.parse() after you fetch the attribute value and before presenting it. This will deserialize it back to a javascript object, array or simple value, depending on your case.

How to select an item by attribute without jquery?

You can do it with document.querySelectorAll('[data-key=' + objectId + ']') and loop through all results

var allKeys = document.querySelectorAll('[data-key=' + objectId + ']');

[].forEach.call(allKeys, function(elem){
   console.log(elem); //Do your stuff with each element
});

Find an element in DOM based on an attribute value

Update: In the past few years the landscape has changed drastically. You can now reliably use querySelector and querySelectorAll, see Wojtek's answer for how to do this.

There's no need for a jQuery dependency now. If you're using jQuery, great...if you're not, you need not rely it on just for selecting elements by attributes anymore.

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There's not a very short way to do this in vanilla javascript, but there are some solutions available.

You do something like this, looping through elements and checking the attribute

If a library like jQuery is an option, you can do it a bit easier, like this:

$("[myAttribute=value]")

If the value isn't a valid CSS identifier (it has spaces or punctuation in it, etc.), you need quotes around the value (they can be single or double):

$("[myAttribute='my value']")

You can also do start-with, ends-with, contains, etc...there are several options for the attribute selector.

How to get data attribute in ie 7?

jQuery can help ... the data attribute works with the data() function in jQuery.

$(srcElement).data('pk');

You can use it with any data attribute, for example, if you had:

<div id="DivId" data-something="foo" data-somethingElse="bar">

You can get the data out by:

$('#DivId').data('something');
$('#DivId').data('somethingElse');

To set data:

$('#DivId').data('something', 'foo');
$('#DivId').data('somethingElse', 'bar');

Here is a link to jQuery .data()

EDIT:

I think you want:

$('.image').click(function () {
    openSlide($(this).data('pk'), false);
});

How to set data attributes in HTML elements

HTML

<div id="mydiv" data-myval="10"></div>

JS

var a = $('#mydiv').data('myval'); //getter

$('#mydiv').data('myval',20); //setter

Demo

Reference

From the reference:

jQuery itself uses the .data() method to save information under the names 'events' and 'handle', and also reserves any data name starting with an underscore ('_') for internal use.

It should be noted that jQuery's data() doesn't change the data attribute in HTML.

So, if you need to change the data attribute in HTML, you should use .attr() instead.

HTML

<div id="outer">
    <div id="mydiv" data-myval="10"></div>
</div>

​jQuery:

alert($('#outer').html());   // alerts <div id="mydiv" data-myval="10"> </div>
var a = $('#mydiv').data('myval'); //getter
$('#mydiv').attr("data-myval","20"); //setter
alert($('#outer').html());   //alerts <div id="mydiv" data-myval="20"> </div>

See this demo

jQuery selectors on custom data attributes using HTML5

$("ul[data-group='Companies'] li[data-company='Microsoft']") //Get all elements with data-company="Microsoft" below "Companies"

$("ul[data-group='Companies'] li:not([data-company='Microsoft'])") //get all elements with data-company!="Microsoft" below "Companies"

Look in to jQuery Selectors :contains is a selector

here is info on the :contains selector

Pass javascript function as data-* attribute and execute

One way is to use eval()

jQuery(".container").on("click", "button.marker", function (e) {
    var callback = jQuery(e.currentTarget).data("callback");

    var x = eval(callback)
    if (typeof x == 'function') {
        x()
    }
});

Demo: Fiddle

Note: Make sure it is safe in your environment, ie there is no possibility of script injection because of bad input from users

• Why is using the JavaScript eval function a bad idea?
• When is JavaScript's eval() not evil?
• eval() isn’t evil, just misunderstood
• Eval is Evil, Part One

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