Analog Clock cannot read the property of null

Question

Can someone explain what I am missing here... the querySelector doesn't appear to be working as I am getting the error "cannot read the property of null" on line 10 my javascript.

const deg = 6;
const hr = document.querySelector("#hr");
const mn = document.querySelector("#mn");
const sc = document.querySelector("#sc");
setInterval(() => {
        let day = new Date();
        let hh = day.getHours() * 30;
        let mm = day.getMinutes() * deg;
        let ss = day.getSeconds() * deg;
        hr.style.transform = 'rotateZ(${hh+(mm/12)} deg)';
        mn.style.transform = 'rotateZ(${mm}deg)';
        sc.style.transform = 'rotateZ(${ss}deg)';
})

Here is the HTML...

    <div class="clock">
    <div class="hour">
        <div class="hr" id="hr"></div>
    </div>
    <div class="min">
        <div class="mn" id="mn"></div>
    </div>
    <div class="sec">
        <div class="sc" id="sc"></div>
    </div>
</div>

https://stackoverflow.com/questions/14028959/why-does-jquery-or-a-dom-method-such-as-getelementbyid-not-find-the-element — epascarello, Apr 22 '20 at 18:45
99.9% sure you are trying to find the element before it is rendered to the page. — epascarello, Apr 22 '20 at 18:46
Next issue is, you are using string literal syntax with a regular string. `'${foo}'` !== `\`${foo}\`` — epascarello, Apr 22 '20 at 18:46
Thanks epascarello... I moved it to the bottom of the page and I am getting the same result. Can you explain what I can do to resolve the literal/regular syntax? — KevMoe, Apr 22 '20 at 18:52

score 0 · Accepted Answer · answered Apr 22 '20 at 19:01

epascarello already gave you the solution but he told you it working here.

const deg = 6;
const hr = document.querySelector("#hr");
const mn = document.querySelector("#mn");
const sc = document.querySelector("#sc");
setInterval(() => {
        let day = new Date();
        let hh = day.getHours() * 30;
        let mm = day.getMinutes() * deg;
        let ss = day.getSeconds() * deg;
        hr.style.transform = `rotateZ(${hh+(mm/12)} deg)`;
        mn.style.transform = `rotateZ(${mm}deg)`;
        sc.style.transform = `rotateZ(${ss}deg)`;
})

.clock > div >div {
  width: 40px;
  height: 5px;
  background: red;
}

<div class="clock">
    <div class="hour">
        <div class="hr" id="hr"></div>
    </div>
    <div class="min">
        <div class="mn" id="mn"></div>
    </div>
    <div class="sec">
        <div class="sc" id="sc"></div>
    </div>
</div>

Analog Clock cannot read the property of null

1 Answers1