单击元素或子元素时如何获取元素的数据属性

Question

I am making a Table .

 document.querySelector('table').addEventListener('click', (e) => { console.log(e.target); console.log(e.target.dataset.item); }) 

 td { padding: 8px; border: 1px solid black; background-color: blue; } span { background-color: red; padding: 4px; } 

 <table> <tr> <td data-item="item1"><span>1</span></td> <td data-item="item2"><span>2</span></td> <td data-item="item3"><span>3</span></td> <td data-item="item4"><span>4</span></td> <td data-item="item5"><span>5</span></td> </tr> </table> 

When I click the BLUE PART , I can get data-item attribute. But when I click the RED PART , I can't.

I wanna fix it, if I click <span/> in <td/> , I want to get data-item attribute from <td /> .

Answer 1

Try to use closest by your child tag instead of dataset .

 document.querySelector('table').addEventListener('click', (e) => { console.log(e.target.closest("td").dataset.item); }) 

 td { padding: 8px; border: 1px solid black; background-color: blue; } span { background-color: red; padding: 4px; } 

 <table> <tr> <td data-item="item1"><span>1</span></td> <td data-item="item2"><span>2</span></td> <td data-item="item3"><span>3</span></td> <td data-item="item4"><span>4</span></td> <td data-item="item5"><span>5</span></td> </tr> </table> 

Answer 2

Check if name of clicked element is span select parent of it using parentNode property

 document.querySelector('table').addEventListener('click', (e) => { var ele = e.target.nodeName == "SPAN" ? e.target.parentNode : e.target; console.log(ele.dataset.item); }) 

 td { padding: 8px; border: 1px solid black; background-color: blue; } span { background-color: red; padding: 4px; } 

 <table> <tr> <td data-item="item1"><span>1</span></td> <td data-item="item2"><span>2</span></td> <td data-item="item3"><span>3</span></td> <td data-item="item4"><span>4</span></td> <td data-item="item5"><span>5</span></td> </tr> </table> 

Answer 3

Why do you listen on the whole table in the first place?

Listen only on "td" elements:

let cells = document.getElementsByTagName('td');
for (var i=0; i < cells.length; i++) {
  let cell = cells[i];
  cell.addEventListener('click', (e) => {
    let element = e.target.nodeName;
    if (element === 'TD') {
      console.log(e.target.dataset.item);
    } else if (element === 'SPAN') {
      console.log(e.target.parentNode.dataset.item);
    }      
  });
}

I don't think setting the listener on the table matters, because in your case, it doesn't trigger the event on the table anyways.

Some styles for better inspection:

table {
  background-color: orange;
  border-spacing: 10px;
}

https://jsfiddle.net/aleks351/p0b46wqs/6/

Answer 4

You could check for the keys in the dataset of the clicked item and if it does have some properties then use e.target otherwise move up one level e.target.parentNode :

 document.querySelector('table').addEventListener('click', (e) => { var el = Object.keys(e.target.dataset).length ? e.target: e.target.parentNode; console.log(el.dataset.item); }) 

 td { padding: 8px; border: 1px solid black; background-color: blue; } span { background-color: red; padding: 4px; } 

 <table> <tr> <td data-item="item1"><span>1</span></td> <td data-item="item2"><span>2</span></td> <td data-item="item3"><span>3</span></td> <td data-item="item4"><span>4</span></td> <td data-item="item5"><span>5</span></td> </tr> </table>