gutter_gup_отстыпы

gutters.js

// Get width gutter
function getWidthGutter(){
  var widthWindow = document.body.clientWidth;
  var widthContainer = document.querySelector('.container').offsetWidth
  var gutters = document.getElementsByClassName('gutter');
  var guttersWidth = (widthWindow -widthContainer)/2;
alert(widthContainer)
  for(var i = 0; i<gutters.length;i++){
    gutters[i].style.width = guttersWidth + 45 + 'px';
  }
}
getWidthGutter();