Display an input's placeholder="" text as a Bootstrap Tooltip on :focus of non-empty form inputs. See this in action at: http://jsfiddle.net/tomhodgins/LEz3Z/2

placeholder-tooltips.js

// Display placeholder="" text as tooltip for :focused, non-empty inputs
$('form input').blur(function() {
  var inputVal = $(this).val(),
      titleText = $(this).attr('placeholder');
  if ( inputVal !=  '' ) {
    $(this).tooltip({
      title: titleText,
      trigger: 'focus',
      container: 'form'
    });
  }
});