IE8~9 Placeholder

IEPlaceholder.js

(function IEplaceholder(o) {
  var agent = navigator.userAgent.toLowerCase();
  var IS_IE = agent.match(/msie\s?(\d{1,2})/g);
  if (!IS_IE || IS_IE[0].substr(5, 6) > 9) return;
  var $placeholders = $('[placeholder]');
  $placeholders
    .wrap('<span />')
    .each(o.addPlaceholder(o))
    .on('keyup', o.keyup)
    .parent()
    .css(o.styles.wrap)
  ;
}({
  styles: {
    wrap: {
      position: 'relative',
      display: 'block'
    },
    text: {
      position: 'absolute',
      left: 0,
      top: 0,
      right: 0,
      bottom: 0
    }
  },
  addPlaceholder: function(o) {
    return function() {
      var $self = $(this),
          $wrap = $self.parent(),
          value = $self.attr('placeholder');
      $('<span />')
        .css(o.styles.text)
        .addClass('ie-placeholder')
        .text(value)
        .appendTo($wrap)
        .on('click', function() {
          $(this).prev().focus();
        })
      ;
    }
  },
  keyup: function() {
    var $placeholder = $(this).next();
    if ($(this).val().length) {
      $placeholder.hide();
    } else {
      $placeholder.show();
    }
  }
}));