input placeholder using elem.value

value-placeholder.js

(function() {
  var canNative = (function() {
    var elem = document.createElement('input');
    return 'placeholder' in elem;
  })();
  $.fn.placeholder = function(text, cls, noNative) {
    var self = this;
    text = text || '';
    cls = cls || 'blur';
    if (!noNative && canNative) {
      if (text) self.attr('placeholder', text);
      self.removeClass(cls);
      return self;
    }

    self.filter(function(i) {
      var elem = this;
      var t = text || elem._placeholder || elem.placeholder || '';
      if (!t) return false;

      elem._placeholder = t;
      elem.placeholder = '';
      if (!elem.value) {
        elem.value = t;
        elem.className += ' ' + cls;
      }
      return true;
    }).focus(function(e) {
      var elem = this;
      var node = $(elem);
      var t = text || elem._placeholder;
      if (node.val() == t) {
        node.val('');
      }
      if (cls) node.removeClass(cls);
    }).blur(function(e) {
      var elem = this;
      var node = $(elem);
      var t = text || elem._placeholder;
      if (!node.val()) {
        node.val(t);
        if (cls) node.addClass(cls);
      }
    }).parents('form').submit(function(e) {
      self.each(function(i, elem) {
        if (elem.value == elem._placeholder) {
          elem.value = '';
        }
      });
    });
    return self;
  };
})();