Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript jQuery Basics Working with jQuery Collections Stopping the Browser's Default Behavior

Samantha Atkinson
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Samantha Atkinson
Front End Web Development Techdegree Graduate 40,307 Points

Event Delegation or Event Propagation? When we append the $pdfCheckbox variable to the parent element #links (div)

const $odd = $('a:odd');
const $secureLinks = $('a[href^="https://"]');
const $pdfLinks = $('a[href$=".pdf"]');
//5.We creates a variable to hold our html
const $pdfCheckbox = $("<label><input type='checkbox'> Allow PDF downloads</label>");

$secureLinks.attr('target', '_blank');

$pdfLinks.attr('download',true);
$secureLinks.addClass('secure');
//Add Flag Locked the pdfLinks 
$pdfLinks.addClass('pdf'); 
//1. Adding a click event to the PDF link using the ON Method
$pdfLinks.on('click', function(event){

  //1. Check that checkbox is clicked
     //2. If zero checkboxes are checked 
  if ($(':checked').length === 0) {

    //2A. prevent download of document
    event.preventDefault();
   //3. Alert the user
    alert('Please check the box to allow PDF Downloads');
  }

});
//7. We appended our variable checkbox to the parent element
$('#links').append($pdfCheckbox);

So what are we doing on the last line Event Delegation or Event Propagation? Or neither? lol

1 Answer

Steven Parker
Steven Parker
231,275 Points

You might call this "DOM Manipulation", and this operation isn't directly related to events. The "append" method adds additional content, typically other elements, to an existing element in the DOM. In this case, it's adding the checkbox which was previously coded in HTML.

For more details, see the jQuery documentation for .append().

Samantha Atkinson
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Samantha Atkinson
Front End Web Development Techdegree Graduate 40,307 Points

Thank you Steven, yes you just confirmed what I thought after posting the question. Delegation and Propagation are related to Events. And you just clarified that that last line is DOM Manipulation.