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JavaScript

Posted by Daniel Hernandez
Daniel Hernandez
13,437 Points

What is wrong with my code? When I run it, the "up" button removes the line like the remove "remove" button does.

I have looked over what the teacher did many times and still cannot seem to find out what is wrong with my code. Here is what I have for HTML

<!DOCTYPE html>
<html>
  <head>
    <title>JavaScript and the DOM</title>
    <link rel="stylesheet" href="css/style.css">
  </head>
  <body>
    <h1 id="myHeading">JavaScript and the DOM</h1>
    <p>Making a web page interactive</p>
    <button id="toggleList">Hide list</button>
    <div class="list">
    <p class = "description">Things that are purple:</p>
    <input type="text" class = "description">
<button class = "description">Change class description</button>
    <ul>
      <li>grapes
        <button class = "up">Up</button>
        <button class = "remove">Remove</button>
      </li>
      <li>amethyst
        <button class = "up">Up</button>
        <button class = "remove">Remove</button>      
      </li>
      <li>lavender
        <button class = "up">Up</button>
        <button class = "remove">Remove</button>
      </li>
      <li>plums
        <button class = "up">Up</button>
        <button class = "remove">Remove</button>
      </li>
    </ul>
      <input type="text" class = "addItemInput">
<button class = "addItemButton">Add item</button>
</div>
    <script src="app.js"></script>

  </body>
</html>

And here is what I have for the javascript.

const toggleList = document.getElementById('toggleList');
const listDiv = document.querySelector('.list');
const descriptioninput = document.querySelector('input.description');
const descriptionp = document.querySelector('p.description');
const descriptionbutton = document.querySelector('button.description');
const listUl = listDiv.querySelector('ul');
const addItemInput = document.querySelector('input.addItemInput');
const addItemButton = document.querySelector('button.addItemButton');

toggleList.addEventListener('click', () => {
              if (listDiv.style.display == 'none')
{                 toggleList.textContent ='hide list';
                 listDiv.style.display = 'block';
}
               else {
                      toggleList.textContent = 'Show list';
                        listDiv.style.display = 'none';
     }          

});

                descriptionbutton.addEventListener('click', () => {
                     descriptionp.textContent = descriptioninput.value + ':'; 
                      descriptioninput.value = "";                            
                        });




listUl.addEventListener('click', (event)=> {
  if ( event.target.tagName == 'BUTTON'){
    if (event.target.className = 'remove'){
         let li = event.target.parentNode;
          let ul = li.parentNode;
          ul.removeChild(li);
  }
  }

    if ( event.target.tagName == 'up'){
         let li = event.target.parentNode;
         let prevLi = li.previousElementSibling;
          let ul = li.parentNode;
      if(prevLi){
          ul.insertBefore(li, prevLi);
               }
    }

});








addItemButton.addEventListener('click', () => {
      let ul = document.getElementsByTagName('ul')[0];                       
      let li = document.createElement('li');
       li.textContent = addItemInput.value;
        ul.appendChild(li);
        addItemInput.value = "";
});

Thanks!

2 Answers

Steven Parker
Steven Parker
243,656 Points
Steven Parker
Steven Parker
243,656 Points

The code is rather difficult to read, but I spotted a few issues:

  • instead of a test (==) for "remove", the className is assigned (=) to "remove" in the "if"
  • the tagName is compared to "up" but it should be the className instead
  • the code that checks for "up" is outside of the test for "BUTTON" but it should be inside

For future postings, use the instructions for code formatting in the Markdown Cheatsheet pop-up below the "Add an Answer" area. :arrow_heading_down:   Or watch this video on code formatting.

Daniel Hernandez
Daniel Hernandez
13,437 Points

Thanks, but I still can't seem to get it to work. Can you look over again what I have in case I screwed up again. Sorry, I am quite new to this all and am still getting the hang of it. The "up" button still won't do anything

listUl.addEventListener('click', (event)=> {
  if ( event.target.tagName == 'BUTTON'){
    if (event.target.className == 'remove'){
         let li = event.target.parentNode;
         let ul = li.parentNode;
         ul.removeChild(li);
  }


    if ( event.target.className == 'up'){
         let li = event.target.parentNode;
         let prevLi = li.previousElementSibling;
         let ul = li.parentNode;
        if(prevLi){
          ul.insertBefore(li, prevLi);
               }
    }
  }
});
Steven Parker
Steven Parker
243,656 Points
Steven Parker
Steven Parker
243,656 Points

Looks good to me. I tried replacing the handler in the original code with this new snippet and it seems to work as expected. Clicking "up" moves the item up.

Daniel Hernandez
Daniel Hernandez
13,437 Points
Daniel Hernandez
Daniel Hernandez
13,437 Points

Sorry for having my code hard to read. I quickly see the value of readability.And thanks! must be something with my browser then