/*
 * Andrew Wayne 2010
 * A fallback for html5 placeholder attribute
*/
var placeholder = {
  isPassword: function(input) {
    return $(input).attr('realType') === 'password';
  },

  valueIsPlaceholder: function (input) {
    return input.value === $(input).attr('placeholder');
  },

  showPlaceholder: function (input, loading) {
    // FF and IE save values when you refresh the page. If the user refreshes the page
    // with the placeholders showing they will be the default values and the input fields won't
    // be empty. Using loading && valueIsPlaceholder is a hack to get around this and highlight
    // the placeholders properly on refresh.
    if (input.value === '' || (loading && placeholder.valueIsPlaceholder(input))) {
      if (placeholder.isPassword(input)) {
        // Must use setAttribute rather than jQuery as jQuery throws an exception
        // when changing type to maintain compatability with IE.
        // We use our own "compatability" method by simply swallowing the error.
        try {
          input.setAttribute('type', 'input');
        } catch (e) { }
      }

      input.value = $(input).attr('placeholder');
      $(input).addClass('placeholder');
    }
  },

  hidePlaceholder: function(input) {
    if (placeholder.valueIsPlaceholder(input) && $(input).hasClass('placeholder')) {
      if (placeholder.isPassword(input)) {
        try {
          input.setAttribute('type', 'password');
          // Opera loses focus when you change the type, so we have to refocus it.
          input.focus();
        } catch (e) { }
      }

      input.value = '';
      $(input).removeClass('placeholder');
    }
  },

  init: function () {
    $(':text[placeholder],:password[placeholder]').each(function(index) {
      var $this = $(this);
      // We change the type of password fields to text so their placeholder shows.
      // We need to store somewhere that they are actually password fields so we can convert
      // back when the users types something in.
      if ($this.attr('type') === 'password') {
        $this.attr('realType', 'password');
      }

      placeholder.showPlaceholder(this, true);

      $this.focus(function() { placeholder.hidePlaceholder(this); });
      $this.blur(function() { placeholder.showPlaceholder(this, false); });
    });
  }
};

// Example usage
Markup: <input placeholder="Enter Name" type="text"/>

JS:
// This example assumes you use Modernizr lib to check for available attributes

if (!Modernizr.input.placeholder) {
  // no placeholder support :(
  // fall back to a scripted solution
  placeholder.init();
}

Fallback for Placeholder

jQuery