Answer 1

You have to use a event handler that triggers your code everytime someone clicks the checkbox.

add onchange="onChangeHandler()" to your input as attribute and wrap your java script into a function. so everytime the checkbox changes the code is executed

also you have to assign the dom element to a variale to use it ! just calling it will do nothing :)

Answer 2

i quickly wrote one myself :

function handler(){
var checkbox = document.getElementById("check");
var body = document.getElementById("body");
if( checkbox.checked){
body.style.backgroundColor="#000000";
}else{
body.style.backgroundColor="#FFFFFF";
}
}

Answer 3

i see no error in your code ? did you fixed it ? ^^

Answer 4

https://code.sololearn.com/WOuQdpk705LL/?ref=app

Answer 5

i think the answer of the question has some links on it

https://stackoverflow.com/questions/4148499/how-to-style-a-checkbox-using-css