Browser Script: Adds an invisible checkbox to the top-right corner of Reddit.com that hides the sidebar when checked. You can add this code to extstyler.js in Extstyler to use this script in Chrome https://github.com/tomhodgins/extstyler

hide-the-side.js

// Add this code to Reddit.com
/* Hide the Side */
if (document.getElementsByTagName('html')[0].classList.contains('reddit')) {
  var input = document.createElement('input'),
      inputCSS = document.createElement('style'),
      inputJS = document.createElement('script');

  input.id = 'hTS';
  input.setAttribute('type','checkbox');
  input.setAttribute('onclick','hideTheSide()');
  if (localStorage.hTS == 'true') {
    input.setAttribute('checked', 'yes')
  }
  inputCSS.innerHTML = '#hTS{position:fixed;top:0;right:0;z-index:999}\
                        #hTS:checked ~ .side{display:none}\
                        #hTS:checked ~ .content{margin-right:0}';
  inputJS.innerHTML = 'function hideTheSide() {\
                        if (localStorage.hTS == "true") {localStorage.hTS = "false"}\
                        else {localStorage.hTS = "true"}\
                      }';

  document.getElementsByTagName('body')[0].insertBefore(input, document.getElementById('header'));
  document.getElementsByTagName('body')[0].insertBefore(inputCSS, document.getElementById('header'));
  document.getElementsByTagName('body')[0].insertBefore(inputJS, document.getElementById('header'));
}