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VisualizaçõesJavascript For loop appends same element once
This is to understand the logic of JS Loop. In the following code i expect that the <li> element will append 3 times inside the <ul> tag. So that i should get 3 <li> tag inside the <ul> tag. As per my understanding any actions inside the loop will work based on the condition. As per that I should get 3 blank <li> tag here. But i get only 1. Anyone can explain whats wrong on my approach and how should i need to write it. Thanks in Advance!
let ul = document.querySelector("ul");
let li = document.createElement("li");
for (i = 0; i <=3; i++) {
ul.appendChild(li);
}
2 Respostas
Responde à pergunta0
You need to create a new element each time. If you are appending the same element multiple times, it will move it in the DOM, but not clone it.
One simple solution is use cloneNode:
let node = document.createTextNode("😀")
for (i = 0; i <3; i++)
document.body.appendChild( node.cloneNode() )Note:
Cloning a node copies all of its attributes and their values, including intrinsic (inline) listeners. It does not copy event listeners added using
0
why
appendChild replace self element bug
solutions
- create new
liinside the loop
const ul = document.createElement("ul");
// li = document.createElement("li");
for (i = 0; i < 3; i++) {
const li = document.createElement("li");
// console.log('i =', i, ul);
ul.insertAdjacentElement('beforeend', li);
}
ul;
// <ul><li></li><li></li><li></li></ul>
- create all children with DOM string
const ul = document.createElement("ul");
let li = '';
for (i = 0; i < 3; i++) {
li += '<li></li>';
}
ul.insertAdjacentHTML('beforeend', li);
ul;
// <ul><li></li><li></li><li></li></ul>
ref
https://developer.mozilla.org/en-US/docs/Web/API/Node/appendChild
https://developer.mozilla.org/en-US/docs/Web/API/Element/insertAdjacentHTML
https://developer.mozilla.org/en-US/docs/Web/API/Element/insertAdjacentElement