How to make a checkbox checked automatically based on a value in Firebase?

Currently I want to make the Checkbox checked automatically based on a value from Firebase. How to make it?

Note: I am using HTML and javascript

I had tried onchange, onload

<div class ="container1">
  <center>
  <label class="switch">
<input type="checkbox" id="lbtnStatus1" value= ""  onclick = 
"btnClick()">
<span class="slider round" ></span>
   </label>
  </center>
 </div>

*Please do not hesitate to ask me to provide more detail, Thanksssss!