自动转换百分比输入值

/**
 * Input Percent
 * 
 * Percentages are tricky to input because users like seeing them as 24.5%, but
 * when using them in calculation their value is actually .245.  This plugin
 * takes a supplied field and automatically creates a percentage input.
 * 
 * It works by taking an input element and creating a hidden input with the same
 * name immediately following it in the DOM.  This has the effect of submitting
 * the proper value instead of the human only one.  An onchange method is then
 * bound to the original input in order to keep the two synced.
 * 
 * Potential Caveats:
 *   * There will be two inputs with the same name.  Make sure anything you
 *     script against this field is prepared to handle that.
 *     
 * @author Brad Koch <kochb@aedisit.com>
 */
(function($) {
    $.fn.inputPercent = function() {
        return this.each(function() {
            var display_field = this;
            var value_field = $('<input type="hidden" />').get(0);
            // Initialize and attach the hidden input.
            $(value_field).attr('name', $(this).attr('name'));
            $(value_field).val($(display_field).val());
            $(display_field).after(value_field);
            $(display_field).after('%');
            // Convert the display field's proper percent value into the display format.
            if (isFinite($(display_field).val())) {
                $(display_field).val($(display_field).val() * 100);
            }
            // Enable synchronization between the two.
            $(this).bind('change', function () {
                var value = $(display_field).val();
                // Handle non-numeric values.
                if (isFinite(value)) {
                    $(value_field).val(value / 100);
                } else {
                    $(value_field).val(value);
                }
            });
        });
    };
})(jQuery);

用法:

$('input.percent').inputPercent();