Get elements by attribute when querySelectorAll is not available without using libraries?

Question

How can you do the equivalent to

document.querySelectorAll(\'[data-foo]\')

where query

Answer 1

I played a bit around and ended up with this crude solution:

function getElementsByAttribute(attribute, context) {
  var nodeList = (context || document).getElementsByTagName('*');
  var nodeArray = [];
  var iterator = 0;
  var node = null;

  while (node = nodeList[iterator++]) {
    if (node.hasAttribute(attribute)) nodeArray.push(node);
  }

  return nodeArray;
}

The usage is quite simple, and works even in IE8:

getElementsByAttribute('data-foo');
// or with parentNode
getElementsByAttribute('data-foo', document);

http://fiddle.jshell.net/9xaxf6jr/

But I recommend to use querySelector / All for this (and to support older browsers use a polyfill):

document.querySelectorAll('[data-foo]');