placeholder.js

/**
 * HTML5 Placeholder Deprecation JS.
 * Automatically support the placeholder attribute in browsers that don't support it.
 * 
 * To emulate webkit, placeHolderActive class should probably contain something like:
 * .placeholderActive { color: darkGray; }
 * 
 * Chris Dary - [email protected]
 * Released under the WTFPL License : http://sam.zoy.org/wtfpl/
**/
if (!('placeholder' in document.createElement('input'))) {
    var showPlaceholder = function () {
        var $this        = $(this),
             placeholder = $this.attr('placeholder');

        if ($this.val() === '' && placeholder) {
            $this.val(placeholder).addClass('placeholderActive');
        }
    };

    var hidePlaceholder = function () {
        var $this       = $(this),
            placeholder = $this.attr('placeholder');

        if (placeholder && $this.val() === placeholder) {
            $this.val('').removeClass('placeholderActive');
        }
    };

    // Look for forms with inputs and/or textareas with a placeholder attribute in them
    $('form').submit(function () {
        // Clear the placeholder values so they don't get submitted
        $('.placeholderActive', this).val('');
    });

    // Clear placeholder values upon page reload
    $(window).unload(function () {
        $('.placeholderActive').val('');
    });

    $(':input').each(showPlaceholder).blur(showPlaceholder).focus(hidePlaceholder);
}