show elements computed style

get-element-styles.js

window.getComputedStyle = window.getComputedStyle || function( element ) {
  return element.currentStyle;
}

//https://stackoverflow.com/questions/22907735/get-the-computed-style-and-omit-defaults
function getStylesWithoutDefaults( element ) {
  var dummy = document.createElement(element.tagName);
  document.body.appendChild( dummy );
  var defaultStyles = getComputedStyle( dummy );
  var elementStyles = getComputedStyle( element );
  var diff = {};
  for( var key in elementStyles ) {
    if(elementStyles.hasOwnProperty(key)
          && defaultStyles[ key ] !== elementStyles[ key ] )
    {
      diff[ key ] = elementStyles[ key ];
    }
  }
  dummy.remove();
  return diff;
}

window.addEventListener("click",function(e){
    let x = e.clientX, y = e.clientY,
    elementMouseIsOver = document.elementFromPoint(x, y)
    var data = getStylesWithoutDefaults(elementMouseIsOver)
    console.log(data)
},false);