Question

I’d like to get all <input /> elements with the placeholder property set, how could I do this without jquery? it should support IE6+, and other popular browsers.

Answer 1

Assuming all the fields have an ID

DEMO

var fieldsWithPlaceholder = [];
var inputs = document.getElementsByTagName("input");
for (var i=0, n=inputs.length;i<n;i++) {
  if (inputs[i].getAttribute("placeholder") !=null) {
    fieldsWithPlaceholder.push(inputs[i].id);
  }
}

alert(fieldsWithPlaceholder);

Update: you can as posted elsewhere test for null, undefined or blank in one go:

if (inputs[i].getAttribute("placeholder")) { // there is something there