jjmu15

// Determine if an element is in the visible viewport
function isInViewport(element) {
  var rect = element.getBoundingClientRect();
  var html = document.documentElement;
  return (
    rect.top >= 0 &&
    rect.left >= 0 &&
    rect.bottom <= (window.innerHeight || html.clientHeight) &&
    rect.right <= (window.innerWidth || html.clientWidth)
  );

jjmu15

// Get image's max-width:100%; in pixels
function getMaxWidth(img) {
  var maxWidth;

  // Check if naturalWidth is supported
  if (img.naturalWidth !== undefined) {
    maxWidth = img.naturalWidth;

  // Not supported, use in-memory solution as fallback
  } else {

jjmu15

// hasClass, takes two params: element and classname
function hasClass(el, cls) {
  return el.className && new RegExp("(\\s|^)" + cls + "(\\s|$)").test(el.className);
}


/* use like below */
// Check if an element has class "foo"
if (hasClass(element, "foo")) {

jjmu15

// This gives us simple dollar function and event binding
var $ = document.querySelectorAll.bind(document);
Element.prototype.on = Element.prototype.addEventListener;

jjmu15

// removeClass, takes two params: element and classname
function removeClass(el, cls) {
  var reg = new RegExp("(\\s|^)" + cls + "(\\s|$)");
  el.className = el.className.replace(reg, " ").replace(/(^\s*)|(\s*$)/g,"");
}

jjmu15

var myObj = document.getElementsByClassName('class');
for (var i = 0; i < myObj.length; ++i) {
    var item = myObj[i];  
    item.innerHTML = 'this is value';
}