javascipt and css code example
Example 1: add css in javascript
document.getElementById("demo").style.display = "none";
Example 2: how to change an element in a different elements code css
/*If the cube is directly inside the container:*/
#container:hover > #cube { background-color: yellow; }
/*If cube is next to (after containers closing tag) the container:*/
#container:hover + #cube { background-color: yellow; }
/*If the cube is somewhere inside the container:*/
#container:hover #cube { background-color: yellow; }
/*If the cube is a sibling of the container:*/
#container:hover ~ #cube { background-color: yellow; }