My vanilla js utilities library

utilities.js

/*
 * These are supported IE9+
 * /

/*
 * Initialization variables and functions
 */
 
  var jsPresent = 'querySelector' in document && 'addEventListener' in window && "classList" in document.createElement("_") ? true : false;
  
  if ( jsPresent ) { document.documentElement.className += 'js'; }
  
/*
 * Object manipulation funtions
 */
  
 var extend = function(obj, src) {
  Object.keys(src).forEach(function(key) { obj[key] = src[key]; });
  return obj;
 }

 var each = function( selector, callbackFunction ) {
  
  len = selector.length;
  
  for (var i=0; i<len; i++) {
   console.log( selector[i].innerHTML );
  }
  
 }
 
/*
 * Class manipulation functions
 * Use classList DOM api https://developer.mozilla.org/en-US/docs/Web/API/Element/classList
 */

/*
 * Selector manipulation methods
 * Use querySelector and querySelectorAll methods https://developer.mozilla.org/en-US/docs/Web/API/Element/querySelector
 * and https://developer.mozilla.org/en-US/docs/Web/API/Element/querySelectorAll
 */

/*
 * Custom JS Starts here
 */
 
  document.addEventListener("DOMContentLoaded", function() {
    
    // Code goes here
    
  });