jquery.placeholder.js

/**
	jQuery placeholder plugin.
	
	Makes browsers that does not support HTML5 placeholder attribute, preform as a modern browser.
	
	Created by:
		Lasse Søberg
		06.04.2011
		
**/
(function($) {
	var native_support = ('placeholder' in document.createElement('input'));
	$.fn.placeholder = function(command) {
		if(!native_support) {
			if(command) {
				switch(command) {
					case 'clear':
						this.each(function() {
							var el = $(this)
							if(el.data('isEmpty') || el.val() == el.attr('placeholder')) {
								el.val('');
							}
						});
					break;
				}
				return this;
			}

			this.each(function() {
				if(!$(this).data('gotPlaceholder')) {
					$(this).focus(function() {
						var el = $(this);
						if(el.data('isEmpty')) {
							el.val('').removeClass('placeholder');
						}
					}).blur(function() {
						var el = $(this);
						if(el.data('isEmpty') || !el.val().length) {
							el.val(el.attr('placeholder')).addClass('placeholder');
						}
					}).keyup(function() {
						var el = $(this);
						el.data('isEmpty', (el.val().length == 0));
					}).data('gotPlaceholder', true);
					
					if(!$(this).val().length || $(this).val() == $(this).attr('placeholder')) {
						$(this).val($(this).attr('placeholder')).addClass('placeholder').data('isEmpty', true);
					}
				}
			});
		}
		
		return this;
	}
})(jQuery);