GetElementByAttr

getElementByAttr.js

var traverseDOM = function(node, fn) {
  fn(node);
  node = node.firstChild;
  while(node) {
    traverseDOM(node, fn);
    node = node.nextSibling;
  }
}


var getElementByAttr = function(attr, val) {
  var result = [];
  traverseDOM(document.body, function(node){
    var valid = node.nodeType===1 && node.getAttribute(attr);
    if(typeof valid === 'string' &&(valid===val || typeof val !== 'string')) { 
      result.push(node);
    }
  });
  return result;
};

console.log(getElementByAttr('class', 'test'));