How can I get a xhtml element by it's ID?
Question
I am trying to get the xhtml element ID in javascript to change an element color when I click a button. I expect the browser to find an element added via an function other than querySelector and getElementById .
As a alternative to the dom default methods, I wrote this function to find element from the nodes tree. I it didn't worked because I used the wrong NodeFilters.
function findById(id) {
const treewalker = document.createTreeWalker(document.body, NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_ATTRIBUTE
| NodeFilter.SHOW_TEXT, { acceptNode: function (node) {
return NodeFilter.FILTER_ACCEPT;
} }, false);
let node;
let nodes = [];
while (node = treewalker.nextNode())
nodes.push(node);
return nodes.filter(node => node.id === id);
}
Here is a minimum reproductable example of what I am trying to do.
/* Display the foobar text (cannot be directly written in the html file) */ let foobar = document.createElement('p'); foobar.innerHTML = 'Foo bar'; foobar.id = 'foobar'; // foobar.setAttributeNS(null, 'id', 'foobar'); document.body.appendChild(foobar); function findById(id) { const treewalker = document.createTreeWalker(document.body, NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_ATTRIBUTE | NodeFilter.SHOW_TEXT, { acceptNode: function (node) { return NodeFilter.FILTER_ACCEPT; } }); let node; let nodes = []; while (node = treewalker.nextNode()) nodes.push(node); return nodes.filter(node => node.id === id); } function displayFoobar() { let e = findById('foobar'); setTimeout(function () { e.style.color = 'blue'; }, 1000); setTimeout(function () { e.style.color = 'black'; }, 2000); } <html> <head> <title>Test</title> </head> <body> <h1>Foo bar app</h1> <button onclick="displayFoobar();">display foobar</button> </body> </html>
1 answers
solution1
1 2022-02-04 00:52:36
Your code with document.getElementById working:
/* Display the foobar text (cannot be directly written in the html file) */ let foobar = document.createElement('p'); foobar.innerHTML = 'Foo bar'; foobar.id = 'foobar'; document.body.appendChild(foobar); function displayFoobar() { let e = document.getElementById('foobar'); setTimeout(function () { e.style.color = 'blue'; }, 1000); setTimeout(function () { e.style.color = 'black'; }, 2000); }
<html> <head> <title>Test</title> </head> <body> <h1>Foo bar app</h1> <button onclick="displayFoobar();">display foobar</button> </body> </html>
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