Simple javascript loop not working

Question

I'm not that experienced yet with JavaScript, so I’m probably overlooking something here:

var products = document.getElementsByClassName('product');
var productsLength = products.length;
for(var i = 0; i < productsLength; i++){
 var productGender = products[i].attr('data-gender');
 if(productGender === triggerVal){
 console.log('yes');
 } else {
 console.log('no');
 }
};

It says: products[i].attr is not a function

I should be able to access it right? The product is just a list item.

Thanks!

• Jaromanda X: that's correct, attr isn't ... use products[i].dataset.gender to get that particular attribute

Answer 1

attr is a jQuery method, use getAttribute

http://www.w3schools.com/jsref/met_element_getattribute.asp

• Tushar: Don't use W3school, add links from MDN as reference

Answer 2

 var productGender = products[i].getAttribute('data-gender');

Is what you need, you have used jquerys .attr()

• Luc: Ah it's working! So it's always better to use getAttribute if that's sufficient?
• BobbyTables: well, is the attribute there in the DOM? Can you show the elements?
• BobbyTables: @luc if you have jQuery availible you should user attr(), if you just write vanilla JS you need to use getAttribute

Answer 3

By far the easiest way to get data-xyz attributes for an element is to use .dataset object

e.g. in your case

var productGender = products[i].dataset.gender;

MDN - https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/dataset

usual warnings - IE11+ only (other browsers have supported it for years) - there's no polyfill

if you need early IE support, then use = getAttribute("data-gender"); as others have suggested

• Tushar: Please also add MDN link for dataset, it'll be easier for OP to read more about it +1

Answer 4

It's because you use Jquery function on DOM element. You should either use native javascript function to retrieve attribute value or you can convert element to Jquery object and then keep using Jquery.

So, instead of

products[i].attr('data-gender');

you can:

$(products[i]).attr('data-gender');