getElementsByAttribute

get-elements-by-attribute.js

function getElementsByAttribute(tag, name, value) {
  var elements  = (tag == "*" && document.all) ? document.all : document.getElementsByTagName(tag),
      matches   = [],
      re        = (typeof name !== "undefined") ? new RegExp("(^|\\s)" + value + "(\\s|$)", "i") : null,
      current,
      attribute;

  for (var i = 0; i < elements.length; i++) {
    current   = elements[i];
    attribute = current.getAttribute && current.getAttribute(name);

    if (typeof attribute === "string" && attribute.length > 0) {
      if(typeof value === "undefined" || (re && re.test(attribute))) {
        matches.push(current);
      }
    }
  }
  return matches;
}