changing checkbox style on uncheck

I have a list of checkboxes in a page with all the boxes are checked by default. When user clicks on any particular checkbox to uncheck it, the background color of the checkbox should be changed or the boxes should be checked with cross mark in a red color.

I tried the following on uncheck,

document.getElementById("checkBooxId1").style = "background-color:red";

This is not working.

Is there any other way?