I use onmouseover and out for <td> or <div> to change either backgroung image or color. However, onmouseover and out are not validated for HTML. w3scholls HTML validator doesn't validate them. How can i solve this problem?
Use the eventListener, instead of assigning it directly on those tags that you have mentioned. The only elements that will validates with those events, are the — <!-- <a> <img .../> <form><elements></form> <area> --> .
And be sure to use only elements that is valid in the DOCTYPE that you are using.