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Why does jQuery or a DOM method such as getElementById not find the element?
(6 answers)
Closed
10 months ago
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I wrote a very simple html css program and add a javascript in it, here is my program and my javascript in it
(my program : https://github.com/phianh2904/phan-8-web-the-band-tablet-responsive)
my javacript in index.html file
<script>
var header = document.getElementById('header');
var mobileMenu = document.getElementById('mobile-menu');
mobileMenu.onclick = function() {
console.log(header.clientHeight);
}
const buyBtns = document.querySelectorAll('.js-buy-ticket')
const modal = document.querySelector('.js-modal')
const modalclose = document.querySelector('.js-modal-close')
const modalcontainer = document.querySelector('.js-modal-container')
// ham hien thi modal mua ve tuc la them class open vao modal
function showBuyTickets() {
modal.classList.add('open')
}
// ham an modal mua ve them class open vao modal
function hideBuyTickets() {
modal.classList.remove('open')
}
// lap qua tung the button va nghe hanh vi click
for (const buyBtn of buyBtns) {
buyBtn.addEventListener('click', showBuyTickets)
}
// nghe hanh vi click vao button close
modalclose.addEventListener('click', hideBuyTickets)
//clcik vao khoang khong de dong cac the con lai
modal.addEventListener('click', hideBuyTickets)
//click vao ben trong thi khong bi lam sao ca
modalcontainer.addEventListener('click', function(event) {
event.stopPropagation()
})
</script>
As you can see in my javascript code snippet, it is very simple. I Wrote the code
var header = document.getElementById('header');
var mobileMenu = document.getElementById('mobile-menu');
mobileMenu.onclick = function() {
console.log(header.clientHeight);
}
to show the clientHeight.
But here is the error I had :
Uncaught TypeError: Cannot set properties of null (setting ‘onclick’)
at index.html:231:28
As they said in this link Uncaught TypeError: Cannot set property ‘onclick’ of null
I put the script in the end of the body element, and wrap code in but it did not work.
So could you please give me some answer for this problem ? Thank you very much for your time.