// 表单序列化，IE9+

HTMLFormElement.prototype.serialize = function() {

    var form = this;

    // 表单数据

    var arrFormData = [], objFormData = {};

    [].slice.call(form.elements).forEach(function(ele) {

        // 元素类型和状态

        var type = ele.type, disabled = ele.disabled;

        // 元素的键值

        var name = ele.name, value = encodeURIComponent(ele.value || 'on');

        // name参数必须，元素非disabled态，一些类型忽略

        if (!name || disabled || !type || (/^reset|submit|image$/i.test(type)) || (/^checkbox|radio$/i.test(type) && !ele.checked)) {

            return;

        }

        type = type.toLowerCase();

        if (type !== 'select-multiple') {

            if (objFormData[name]) {

                objFormData[name].push(value);

            } else {

                objFormData[name] = [value];

            }

        } else {

            [].slice.call(ele.querySelectorAll('option')).forEach(function(option) {

                var optionValue = encodeURIComponent(option.value || 'on');

                if (option.selected) {

                    if (objFormData[name]) {

                        objFormData[name].push(optionValue);

                    } else {

                        objFormData[name] = [optionValue];

                    }

                }

            });

        }

    });

    for (var key in objFormData) {

        arrFormData.push(key + '=' + objFormData[key].join());

    }

    return arrFormData.join('&');

};