jQuery not loading

[johnpitchko]

Followed the instructions provided.

Added gem 'jquery-rails' to my Gemfile. Did bundle update and confirmed that I sawUsing jquery-rails 4.4.0` in the output.

Added the following to app/assets/javascripts/application.js:

//= require jquery
//= require rails-ujs

To test that jQuery works, I added the following to one of my index.erb files:

<script>
  window.onload = function() {
    if (window.jQuery) {
        // jQuery is loaded
        alert("Yeah!");
    } else {
        // jQuery is not loaded
        alert("Doesn't Work");
    }
}
</script>

When I restart rails and refresh the page, I receive the Doesn't work alert.

However, if I add the usual jQuery script tag to the page:

<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>

I receive the Yeah! alert.

Am I missing something here? TIA

[toadslop]

I also can't get jquery to load. Can't find any explanation on the internet about why.

[michaeldawson]

Same issue here.

[joaku]

If you are using webpacker (gem 'webpacker'), then to have to map the $ an jquery instructions to the compiling:

config/webpack/enviroment.js

var webpack = require('webpack');

const { environment } = require('@rails/webpacker')

environment.plugins.prepend('Provide',
    new webpack.ProvidePlugin({
        $: 'jquery',
        jQuery: 'jquery',
        Popper: ['popper.js', 'default']
    }));

module.exports = environment