JQuery based dom selector part 1.

domSelector.js

(function (){
    var newcss = ".mouseOn{background-color: #bcd5eb !important;outline: 2px solid #5166bb !important;}";
    
    if ('\v'=='v') /* ie only */ {
        document.createStyleSheet().cssText = newcss;
    } else {
        var tag = document.createElement('style'); 
            tag.type = 'text/css'; document.getElementsByTagName('head')[0].appendChild(tag); 
            tag[ (typeof document.body.style.WebkitAppearance=='string') /* webkit only */ ? 'innerText' : 'innerHTML'] = newcss;    
    }
})();

prevElement = null;

document.addEventListener (
  'mousemove',
  function(e) {
      var elem = e.target || e.srcElement;
      if (prevElement!= null) {prevElement.classList.remove("mouseOn");}
      elem.classList.add("mouseOn");
      prevElement = elem;
  },
  true
);